Tubular Structures with Variable Support

ABSTRACT

A lumenal element configured to transit a body lumen comprising a lumenal member ( 102 ) and an outer member ( 200 ) disposed over at least part of the lumenal member with a structural support ( 350 ), e.g. a mesh or stent, having a facing surface facing a surface of the lumenal member and wherein the facing surface includes at least one non-smooth surface portion, discontinuity, or non-uniformity, wherein the structural support is between the lumenal member and the outer member wherein the outermember is at least partly sealed to adjacent surfaces of the lumenal member sufficient to withstand fluid pressure within a space about the structural support, wherein the lumenal member has a first flexibility in the area of the structural support, and increasing the flexibility of the area of the structural support by moving at least a part of the outer member out of contact with the structural support. The flexibility of a lumenal element can be changed. Also disclosed a method of assembly of the lumenal element.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. 62/367,634 filed Jul. 27, 2016,and is related to U.S. 62/125,294, filed Jan. 20, 2015, U.S. 62/196,902,filed Jul. 24, 2015, and PCT/US2016/014193, published as WO2016/118671,the disclosures of which are incorporated herein by reference.

BACKGROUND

These inventions relate to flexible shafts, including shafts havinglumens and to shafts tubular structures, including both of those thatmay be suitable for transiting mammalian lumens, including vasculatureand other lumens, including for humans, to such structures havingvariable support, and to catheters.

SUMMARY

In one example of lumenal members, a flexible lumenal member includes aninner member and has an outer member outside of the inner member. Amedial member is between the inner and outer members, wherein the outermember is collapsible about the medial member and wherein the outermember and the medial member are configured such that collapse of theouter member about the medial member increases a stiffness of theassembly by contact between a surface or surfaces of the medial memberwith a surface or surfaces of an adjacent member or members. The medialmember may be a support structure or an assembly of elements including asupport structure, where the support structure has a surface or surfacesthat may include surface discontinuities, in one example in the form ofraised structures or cavities forming surface discontinuities, and suchsurface discontinuities may increase a frictional engagement between themedial member and an adjacent surface when they come into contact. Inone example, the support structure is a mesh or stent, including any ofthe stent or stent-like structures described herein, or any othersupport structures or similar structures as those described herein. Inan example where a medial member extends longitudinally and the supportstructure has an inside surface having surface discontinuities, aninside dimension of the support structure spanning the interior of thesupport structure may vary longitudinally, for example as a function ofthe variations in the surface discontinuities, and also may varyarcuately or rotationally around the interior of the support structureat any given longitudinal position. For example, where the surfacediscontinuities are formed by raised structures, the spacing across theinterior of the support structure from a raised structure to a surfaceon the opposite side may be a first distance and the spacing across theinterior of the support structure from a point adjacent a raisedstructure to a surface on the opposite side may be a second distancegreater than the first distance. Where the support structure forms aright circular cylinder, the distances would be equivalent to the insidediameters. In an example where a support structure extendslongitudinally and has an outside surface having surfacediscontinuities, an outside dimension of the support structure spanningthe support structure may vary longitudinally, for example as a functionof the variations in the surface discontinuities, and also may varyarcuately or rotationally around the exterior of the support structureat any given longitudinal position. For example, where the surfacediscontinuities are formed by raised structures, the spacing from anouter surface of the raised structure to the opposite side of thesupport structure may be a first distance and the spacing from an outersurface adjacent the raised structure to the opposite side of thesupport structure may be a second distance less than the first distance.Where the support structure forming at least part of the medial memberforms a right circular cylinder, the distances would be equivalent tooutside diameters. Medial members forming or incorporating supportstructures as described in this paragraph and medial members forming orincorporating support structures such as described elsewhere herein canbe used in any of the assemblies described herein.

In an example of a support structure such as one that may be used as orwith a medial member in any of the assemblies described herein, thesupport structure may be in the form of a stent, stent-like structure ormesh structure, including any of those described herein or similarthereto, and may include on at least one surface of the supportstructure a raised structure, for example a raised structure extendingoutward relative to the at least one surface of the support structure.In one example, a raised structure can extend away from the adjacentsurface, or a raised structure can be formed as a structure adjacent oneor more cavities in material adjacent the raised structure. In anexample, a support structure, for example a stent, in one example astent around a portion of an inner tubular structure and within an outertubular member (including any of those described herein), includes aplurality of limbs wherein at least one limb includes at least oneraised structure extending toward an interior of the support structure.The limb has a thickness, and the raised structure extends a distanceless than the thickness of the limb. The limb has a surface area, and asurface area of the raised structure is less than the surface area ofthe limb. In one example, the limb includes a plurality of raisedstructures. In a further example, the support structure includes aplurality of limbs, and at least some of the plurality of limbs includesrespective raised structures. When the support structure is includedaround a portion of an inner tubular structure, any raised structurescan contact respective adjacent surfaces on the inner tubular structure,and such contact can resist movement or geometry changes of an assemblyin which the support structure is included. In other examples of supportstructures described herein, the surface geometries facing the adjacentsurfaces on the inner tubular structure or the outer tubular member canbe uniformly smooth or without surface discontinuities or withoutsurface variations.

In one configuration, the inner member includes a lumen, for examplewhich can receive a component, including but not limited to a guidewire,dilator, therapeutic device, intervention device and/or othercomponents. In that or another configuration, the medial member can takea number of configurations. In one example of a configuration of themedial member, the medial member can be a stent, for example a stentthat is generally understood in the medical industry as being forimplanting into a body, or the medial member can be a skeleton ormovable support structure for example that may be bendable, flexible orotherwise movable, including skeletons or movable support structureshaving linear or curving segments separated by open spaces. The linearand/or curving segments can have a repeating pattern or a non-repeatingpattern. In any of the foregoing or additional configurations, themedial member may be enclosed within an envelope, for example one whichprevents contact between the medial member and vasculature into whichthe assembly can be inserted. In one configuration, the medial membermay be sealed within a cavity, in one example an annular cavity, and inanother configuration, the medial member may be enclosed within a cavitythat is fully sealed or closed but for one or more fluid passageways forallowing fluid to enter and exit the cavity.

In another example of lumenal members, including any of the foregoingexamples and configurations, a flexible lumenal member includes an innermember, over a portion of which an intermediate structural memberextends. An outer member extends over at least part, and in the presentexamples all, of the intermediate structural member. In a relaxed stateof the flexible lumenal member, the intermediate structural member andthe outer member, the intermediate structural member has a first outerdimension, in at least some examples an outer diameter, and the outermember has at least one second inner dimension, in at least someexamples an inner diameter, less than the first outer dimension of thestructural member. In such a configuration, the outer member may bebiasing or pressing against the intermediate structural member towardthe inner member. For example, the outer member can have an uninflatedor unexpanded configuration that presses against the intermediatestructural member. In one configuration, the unassembled outer member ina relaxed configuration has an inner diameter that is less than theouter diameter of the intermediate structural member in theconfiguration of the intermediate structural member when it ispositioned on the inner member. In one example where the unassembledouter member has an inner diameter less than the outer diameter of theintermediate structural member when the outer member is in a relaxedconfiguration, the outer member can be expanded or enlarged sufficientlyto slide over the intermediate structural member and positioned asdesired, and then released, in which case the outer member returnstoward the relaxed configuration, pressing on the intermediatestructural member. For example, the outer member is resilientlyflexible. The intermediate structural member, either alone or with theinner member, stops the further relaxation of the outer member. With thefinal assembly, and when the apparatus is ready for use, theintermediate structural member is under compression from the resiliencyof the outer member.

In another example of a lumenal structure, a lumenal element or atubular element may combine with one or more additional elements to forma nested structure, at least two components of which may be concentric,at least two components of which may be tubular, and in which one ormore structural support elements may be positioned intermediate thelumenal or tubular element and an outer element. In one configuration ofthe structural support element, the structural support element has askeleton or framework configuration, for example a plurality ofinterconnected straight or curved elements separated by open spaces. Inone example, a plurality of interconnected straight or curved elementscan be highly interconnected, or sparsely interconnected or in between.The straight or curved elements can be struts, each one of which can beinterconnected at respective ends with one or more other struts, atnodes. A node can have two struts, thereby contributing to a moresparsely interconnected structure, three struts thereby contributing toa greater interconnected structure, four struts contributing toward agreater interconnected structure, and so on. Similarly, all nodes canhave the same number of struts, or there can be groups of nodes havingdifferent numbers of struts where a given group has the same number ofnodes, which also contributes to the level of interconnectedness. Thestructural support element can have articulating members, and/or mayinclude a cellular structure interconnected by one or more links, forexample struts. In a number of examples, the structural support elementcan be a stent, for example a stent that is generally understood in themedical industry as being for implanting into a body, for any of anumber of procedures. The stent can be an open cell stent, closed cellstent, hybrid cell stent, slotted tube stent, or other stentconfiguration, including mesh tubes generally. Examples of a stentinclude the flexible-expandable stent configurations shown in U.S. Pat.No. 5,843,120. The structural support element is flexible, andreturnable to its original form without losing substantially theoriginal form. It may also be collapsible and expandable without losingsubstantially the original form.

In any of the examples of an intermediate structural member describedherein, the intermediate structural member can be positioned within anenclosure, for example an outer tubular element, which enclosure issecured to an inner lumenal element or tubular element such that theintermediate structural member is between the enclosure and the innerlumenal element or inner tubular element. The enclosure may be sealedwhile still permitting fluid communication with a source of pressurizedfluid to enlarge or inflate, for example with a liquid or a gas, theenclosure. In one example, the enlargement occurs by way of expansion ofthe enclosure in the form of an outer cover, for example an outertubular element. In some examples, the enlargement releases theintermediate structural member, allowing it to move more freely.

In any of the examples of the intermediate structural members, medialstructural members, stents or tubular meshes referenced herein, suchstructural member can include inner and/or outer peripheral surfacesthat can frictionally engage adjacent surfaces of the assembly. Forexample, with a structural member extending between an inner tubularelement and an outer tubular element, the surfaces of the structuralmember contacting one or the other of the inner tubular element and theouter tubular element can press sufficiently into the surface orsurfaces to help limit relative movement therebetween. In someconfigurations, surfaces on the structural member can be sufficientlywell-defined to have a perceptible angle or non-round surface that canhelp to limit relative movement between the structural member and theadjacent tubular member. In other configurations, a surface finish onthe structural member can help to increase the frictional force requiredto move the structural member and the adjacent contacting surface orsurfaces relative to each other. Such structural members can be metal,including but not limited to nitinol, stainless steel and similarmetals, polished or unpolished, or other materials.

In a further example, which may be configured with any of the foregoingexamples or configurations, the examples of intermediate structuralmembers may be used in a variable stiffness catheter. In one example,the catheter has a first flexibility in one condition and a secondflexibility in a second condition. The one condition can be an inflatedouter envelope, outer tube or outer element around a structural supportelement, which structural support element is on a lumenal element of thecatheter. The outer element is enlarged or inflated to allow anincreased flexibility in the catheter. The outer element can be enlargedor inflated an amount sufficient to reduce a surface area of contactbetween the outer element and the structural support element, which mayleave a surface area of contact between the outer element and thestructural support element of anywhere from 95% to zero. A reducedsurface area of contact can result in greater flexibility of at least aportion of the lumenal element, in the present example the catheter.Reduced or zero surface area of contact between the structural supportelement and the outer element increases the freedom of movement of thecatheter in the area of the structural support element, for example sothat any contribution of frictional engagement between the structuralsupport element and the outer element is reduced or eliminated, with theremaining resistance to movement being contributed by the structuralsupport element itself, the inner lumenal element and any surface areaof contact between the two of them. If the outer element is constricted,reduced, deflated or otherwise brought into greater contact with thestructural support element (for example by withdrawing fluid or byotherwise applying vacuum or negative pressure or by elastic tension inthe outer element), flexibility of at least a portion of the lumenalelement, the catheter in this example, is reduced, for example arisingfrom greater frictional contact between the outer element and theadjacent surface or surfaces of the structural support element. In oneconfiguration of the foregoing, enlargement or inflation of the outerelement occurs by injection or intrusion of a media, for example afluid, for example a liquid such as saline, into the area of thestructural support element. The fluid pressure can be used to increaseor enlarge the outer element for example increasing the outer dimensionof the outer element so that the inner surface of the outer element nolonger contacts one or more adjacent surfaces of the structural supportelement. In one example, the outer element is enlarged or inflatedsufficiently to eliminate all contact with the structural supportelement. The fluid can be a mixture of saline and contrast, a gas suchas CO2, or other appropriate fluids. In some configurations, release ofthe outer element from the structural support element also helps torelease the structural support element from the inner lumenal element ofthe catheter, for example to reduce or eliminate frictional engagementbetween the structural support element and the adjacent surface of theinner lumenal element of the catheter.

In a further example, which may be configured with any of the foregoingexamples or configurations, the examples of intermediate structuralmembers, may be used in a variable stiffness catheter whereby thestiffness of a portion of the catheter is changed by pressing orcontacting a structural support element, which structural supportelement is contained within a cavity or otherwise unremovable from thecatheter without damaging the catheter, and changed again by unpressingor removing contact with the structural support element. In one example,the catheter has a structural support element in a cavity of thecatheter and fluid is used in the cavity to allow or remove contact withthe structural support element as desired. In one example, fluid is usedto pressurize the cavity and reduce the amount of contact with thestructural support element, and reducing pressure increases the amountof contact with a structural support element. In one example of reducingpressure to increase the amount of contact with a structural supportelement, an inherent resiliency in an outer element can be used toincrease contact between the outer element and the structural supportelement when fluid pressure is reduced. Alternatively, an increase inpressure can be used to increase frictional contact with such astructural support element, depending on design of the assembly.

In another example, which may be configured with any of the foregoingexamples or configurations, the examples of intermediate structuralmembers may be used in a catheter having an inner lumenal member, astructural support element, for example a stent, tubular mesh, or otherstructural member, and the catheter may further include an outer tubularelement over at least part of the structural support element wherein theouter tubular element is configured to be in a normally collapsed state.In one configuration, the normally collapsed state is one that occursthrough elastic contraction of the material of the outer tubularelement, and in one configuration the elastic contraction appliespressure to the structural support element. Pressure against thestructural support element produces a frictional force between thestructural support element and the material of the outer tubular elementto inhibit movement therebetween. In one example, an outer tubularelement is expanded and placed over the structural support element onthe lumenal element, and then allowed to release or collapse about thestructural support element, for example configured to apply an inwardpressure on the structural support element. The outer tubular elementcan be generally uniform in geometry and material throughout its length,but also can have different characteristics incorporated into the outertubular element over its length and/or circumference, for examplevariations in durometer, thickness, geometry as well as construction(for example single piece versus multiple piece).

In a further example, which may be configured with any of the foregoingexamples or configurations, intermediate structural members may be usedin a catheter having an inner lumenal member, an outer tubular member,and a structural support member positioned between the inner lumenalmember and the outer tubular member whereby increasing or decreasingcontact between one or more surfaces of the structural support memberwith one or both of the inner lumenal member and the outer tubularmember changes a stiffness of a portion of the catheter. Increasing ordecreasing contact can be done by inflation or enlargement, for exampleinflation or enlargement of the outer tubular member and/or the innerlumenal member, for example sufficient to decrease the surface area ofcontact of one or more elements with one or more surfaces of thestructural support member. In one example, flexibility of the cathetercan be increased by enlarging the outer tubular member relative to thestructural support member, for example by injection of fluid into acavity around the structural support member. Flexibility of the cathetercan be decreased by reducing the enlargement, for example by removingfluid from a cavity around the structural support member.

In another example, which may be configured with any of the foregoingexamples or configurations, a catheter has a tubular mesh having aplurality of longitudinally extending struts interconnected by aplurality of connecting struts. Individual ones of the plurality ofconnecting struts can connect respective circumferentially or arcuatelyspaced longitudinal struts. In one example, a series of alignedlongitudinal struts are circumferentially or arcuately spaced fromanother series of aligned longitudinal struts, and offsetlongitudinally. In another example, respective angles between aconnecting strut and a respective longitudinal strut are acute angles.The acute angles can be angles anywhere between greater than zero andless than 90°.

In a further example, which may be configured with any of the foregoingexamples or configurations, an intermediate structural member may beused between the inner and outer tubular elements for providingvariability in stiffness of the assembly. In one configuration, theintermediate structural member is a flexible cylindrical membercomprising a plurality of elements wherein a transverse cross-section ofthe flexible cylindrical member includes at least two, and in manyexamples at least three, elements arranged around the cylinder. In oneconfiguration, the plurality of elements are interlinked orinterconnected within the intermediate structural member. In a furtherconfiguration, the plurality of elements have discrete lengths, and inanother configuration each of the plurality of elements have lengthsthat are less than the overall length of the structural support member,and in one configuration none of the plurality of elements extendproximally to a manual control apparatus or to a proximal catheter hub.In another configuration, the plurality of elements are different sizes,and may include different cross-sectional areas, and the plurality ofelements may be identifiable in groups, one group having the samecharacteristics different from those in another group, for exampledifferent cross-sectional areas, different sizes, different lengths, andthe like. In one example, there is a larger number of elements from onegroup in the intermediate structural member than the number of elementsfrom another group. In one example, the plurality of elements areuniformly distributed over the cylinder when in a relaxed or neutralstate. In one example, the intermediate structural member includes twogroups of interconnected elements, the first group arranged in atransverse cross-section to have a first number of elementssubstantially evenly distributed about the cylinder, and the secondgroup to have a second number of elements substantially evenlydistributed, in one configuration six from the first group and 12 fromthe second group. The plurality of elements forming the intermediatestructural member in one example are arranged in a substantiallysymmetrical form when in the relaxed or neutral configuration.

In a further example, which may be configured with any of the foregoingexamples or configurations, a variable stiffness shaft, for exampletubular elements, lumenal elements, catheters, and the like, may includea structural support member arranged relative to the shaft such that theshaft can be changed from a first shape configuration, such as a shapeconfiguration as manufactured, to a second different shape configurationand the structural support member helps to keep the shaft in the secondshape configuration. The structural support member can help to keep theshaft in the second shape configuration even in spite of application ofsome external forces, or even in spite of manufactured memory such asthe original manufactured shape. In one configuration, the structuralsupport member can be in a first configuration, for example a releasedor flexible configuration, and the shaft in the location of thestructural support member can be changed or reshaped to a second shapeconfiguration at which the structural support member is then fixed orstiffened, clamped or sandwiched to retain its then configuration. As aresult, the shaft in the area of the structural support member thenmaintains its second shape configuration, and that portion of the shaftis inhibited from returning to its first shape configuration, even inthe presence of external forces on the shaft or inherent memory in thefirst configuration. In one example, a catheter can be introduced into atortuous body lumen with a structural support member associated with thecatheter in a released or flexible configuration. Once the catheter isin the desired position within the body lumen, with whatever twists andturns imposed on it while transiting the body lumen, the structuralsupport member can be stiffened, clamped or sandwiched in itsthen-existing second shape, and that portion of the catheter associatedwith the structural support member is held in the same shape. Duringstiffening or while the catheter portion has an increased stiffness,little or no force is applied to the vessel walls by the catheter.Therefore, the structural support member helps to impose on that portionof the catheter the shape of the body lumen in which it is positioned,giving that portion of the catheter a shape memory that is maintainedeven in the presence of external forces and/or any shape memoryinstilled at manufacture. An outer tubular element also helps to fix,stiffen, clamp or sandwich the structural support member in theseexamples. Therefore, a flexible shaft element, including medicalcatheters, can be stiffened and maintained in a large number of shapesconfigurations regardless of a starting shape configuration ormanufactured shape configuration.

In another example of a medial member, the medial member can include anassembly of at least one structural support member and a secondarymaterial. The secondary material may extend interior to or exterior tothe structural support member, or the structural support member may beembedded in or enclosed in the secondary material. In one example, thesecondary material can extend between the structural support member andan inner tubular member, and in another example the secondary materialcan extend between the structural support member and an outer tubularelement. In a further example, the structural support member may beencased in or embedded in the secondary material. The secondary materialmay be a plastic, fabric, or other material suitable for theapplication, for example for increasing or decreasing relative movementbetween the structural support member and adjacent surfaces as desired.

In an example of a medial member formed as an assembly, the medialmember can include a plurality of structural support members, forexample a first structural support member extending longitudinally, anda second structural support member laterally outward of the firststructural support member, or encircling the first structural supportmember or where the first structural support member is nested inside thesecond structural support member. The first and second structuralsupport members may have identical configurations or differentconfigurations, where each structural support member can have aconfiguration such as described herein. The medial member may alsoinclude a secondary material between the first and second structuralsupport members. The secondary material may be a sleeve extending aboutthe first structural support member, and may be a film, a perforated orporous membrane or material, and may be configured to allow free slidingmovement between the first and second structural support members, or forincreasing frictional engagement between the first and second structuralsupport members.

In another example of flexible lumenal members having an inner memberand an outer member outside of the inner member, the outer member mayinclude a support structure forming part of the outer member, forexample embedded within the outer member or attached to or forming partof an internal or interior surface of the outer member.

As used herein, “outer” in the context of outer tubular member, outermember, outer element, outer cover, outer envelope or outer wall refersto a position relative to the structural support member, and “outer” inthis context does not mean outer-most.

These and other examples are set forth more fully below in conjunctionwith drawings, a brief description of which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevation view of a catheter assembly in accordancewith one aspect of the present inventions.

FIG. 2 is a longitudinal cross section of the catheter assembly of FIG.1.

FIG. 3 is a detail of the cross section of the assembly of FIG. 2.

FIG. 4 is a detail of the cross-section illustrated in FIG. 3.

FIG. 4A detail of a portion of the cross section of FIG. 4 taken at 4A.

FIG. 5 is a longitudinal cross section of the catheter assembly of FIG.1 with a portion of the catheter enlarged or inflated.

FIG. 6 is a detail of the enlarged or inflated portion of the catheterassembly illustrated in FIG. 5.

FIG. 7 is a longitudinal cross section of a portion of the catheterassembly of FIG. 1.

FIG. 8 is a longitudinal cross section of another example of a catheterassembly.

FIG. 9 is a longitudinal cross section of the catheter assembly of FIG.8 with a portion of the catheter enlarged or inflated.

FIG. 10 is an isometric view of a portion of a catheter assembly.

FIG. 11A is a transverse cross-section of the catheter portion of FIG.10.

FIG. 11B is a detail of a section of the catheter portion of FIG. 10taken at an angle as illustrated in FIG. 11A, though not necessarily atthe axial location illustrated in FIG. 11A.

FIG. 12 is a schematic of a mesh pattern for use as a structural supportelement for a catheter.

FIG. 13 is a transverse section of two struts in the mesh pattern takenalong line 13-13 of FIG. 12.

FIG. 14 is a schematic representation of a tubular mesh formed using thepattern of FIG. 12.

FIG. 15 is a schematic representation of the tubular mesh of FIG. 14 ina loaded or bent configuration.

FIG. 16 is a schematic representation of a mesh pattern for use as astructural support element.

FIG. 17 is a schematic representation of a further mesh pattern for useas a structural support element.

FIG. 18 is a schematic representation of a catheter assembly invasculature, for example human vasculature, with a guide element.

FIG. 19 is a schematic representation of a catheter assembly in thevasculature of FIG. 18 advanced with the assistance of a guide element.

FIG. 20 is a schematic representation of a catheter assembly in thevasculature of FIG. 18 with an intervention device in place.

FIG. 21 is a schematic representation of a mandrel and a catheter shaftbeing assembled there on.

FIG. 22 is a schematic representation of the schematic of FIG. 21 with astructural support element assembled there on.

FIG. 23 is a schematic representation of the assembly of FIG. 22 with aballoon inflation and assembly apparatus.

FIG. 24 is a schematic representation of the assembly of FIG. 23 with atubular element inflated.

FIG. 25 is a schematic representation of the assembly of FIG. 24 withthe mandrel assembly being inserted into the inflated tubular element.

FIG. 26 is a schematic representation of the assembly of FIG. 25 withthe mandrel inserted into the inflated tubular element and the tubularelement deflated.

FIG. 27 is a schematic representation of the mandrel assembly of FIG. 21with the catheter assembled there on.

FIG. 28 is a schematic representation of a further mandrel assembly withthe catheter assembled there on configured to provide the catheter foran interference fit with a dilator assembly.

FIG. 29 is a longitudinal cross section of another example of a catheterassembly similar to the catheter assembly of FIGS. 8-9 with anotherexample of a structural support.

FIG. 30 is a detail of a distal end portion of the catheter of FIG. 29.

FIG. 31 is a longitudinal cross section of the catheter assembly of FIG.29 with a portion of the catheter assembly reduced or deflated orconstricted.

FIG. 32 is a detail of a distal end portion of the catheter of FIG. 31.

FIG. 33 is a schematic and plan view of part of a catheter assemblyshowing an alternative inflation lumen over a portion of the catheterwherein the alternative inflation lumen can provide structural supportfor the adjacent portion of the catheter.

FIG. 34 is an isometric and transverse cross-sectional view of a portionof the catheter assembly of FIG. 33.

FIG. 35 is a plan view of the catheter assembly portion of FIG. 33wherein the inflation lumen is shown in a collapsed configuration with apleat over the adjacent portion of the catheter lumen.

FIG. 36 is an isometric and transverse cross-sectional view similar toFIG. 34 wherein the inflation lumen is shown in a collapsedconfiguration with a pleat as represented in FIG. 35.

FIG. 37 is a longitudinal cross section of another example of a catheterassembly similar to the catheter assembly of FIGS. 8-9 with anotherexample of an assembly for varying or controlling a stiffness of aportion of the catheter assembly, and with an inflation lumen in anexpanded, enlarged or inflated configuration.

FIG. 38 is a detail of a distal portion of the catheter of FIG. 37.

FIG. 39 is a view similar to that of FIG. 37 with the inflation lumen ina reduced, constricted or deflated configuration.

FIG. 40 is a detail of a distal portion of the catheter of FIG. 39.

FIG. 41 is a longitudinal cross section of another example of a catheterassembly similar to the catheter assembly of FIGS. 8-9 with anotherexample of an assembly for varying or controlling a stiffness of aportion of the catheter assembly, and with an inflation lumen combinedwith a support structure, in an expanded, enlarged or inflatedconfiguration.

FIG. 42 is a detail of a distal portion of the catheter of FIG. 41.

FIG. 43 is a view similar to that of FIG. 41 with the inflation lumen ina reduced, constricted or deflated configuration.

FIG. 44 is a detail of a distal portion of the catheter of FIG. 43.

FIG. 45 is a schematic and plan view of a pattern for use as astructural support element for use with or as a medial member, forexample in a catheter or similar assembly.

FIG. 46 is a detail and schematic and longitudinal cross section of aportion of a wall having an enlarged or inflated portion in an assemblyanalogous to the assembly illustrated in FIG. 6 showing the alternativestructural support element of FIG. 45 for such an assembly.

FIG. 47 is a detail and schematic and longitudinal cross section of theassembly of FIG. 46 analogous to the assembly illustrated in FIG. 4showing the structural support element and outer tubular elementcollapsed or deflated with raised structures contacting an adjacentsurface of a lumen structure.

FIG. 48 is a longitudinal cross section of a catheter assembly similarto that shown in FIGS. 8-9 with a medical device in the form of adiagnostic or therapy device associated with the catheter.

DETAILED DESCRIPTION

This specification taken in conjunction with the drawings sets forthexamples of apparatus and methods incorporating one or more aspects ofthe present inventions in such a manner that any person skilled in theart can make and use the inventions. The examples provide the best modescontemplated for carrying out the inventions, although it should beunderstood that various modifications can be accomplished within theparameters of the present inventions.

Examples of lumenal or tubular structures and of methods of making andusing the lumenal or tubular structures are described. Depending on whatfeature or features are incorporated in a given structure or a givenmethod, benefits can be achieved in the structure or the method. Forexample, tubular structures using inner and outer tubular elements,which may but need not be concentric, may be configured to have onestiffness in a first state and another stiffness in another state, forexample may be configured to be relatively rigid when in a relaxedstate, and less rigid when one or more elements in the tubularstructures are activated. Inner and outer tubular elements can also beconfigured with an intermediate structural framework that can provide amore reliable support assembly when in a support configuration, forexample when the inner and outer tubular elements and the structuralframework are pressed together. Configurations of inner and outertubular elements may also be used to more securely releasably fix thetubular elements in a desired geometry, for example to support passageof another element, for example an interventional device or otherdevice, during a procedure.

Examples of inner and outer lumenal element or tubular elements andmedial member forming intermediate structural frameworks can also beused to provide a more reliable support structure per unit length of anassembly of the tubular elements and structural framework. Elements ofone or more of the inner and outer tubular elements and structuralframework can be configured to incorporate a desired flexibility orstiffness per unit length. In one example, a structural framework can beused intermediate the inner and outer tubular elements that provides agiven flexibility or stiffness per unit length, and a differentstructural framework can be used to manufacture or assemble anothercombination having a different flexibility or stiffness per unit length.In another example, a structural framework can be used to provide agiven flexibility or stiffness as a function of inflation or deflationof a component adjacent the structural framework. In one configuration,the structural framework can provide an increased stiffness when anadjacent component presses against it, for example when deflation bringsthe component into contact with the structural framework, and canprovide a decreased stiffness when the adjacent component has a reducedamount of contact with the structural framework.

In some configurations of lumenal or tubular structures, improvementscan be achieved also in assembly, and in some configurations, assembliescan be produced having an assembled or final configuration with adesired stiffness or flexibility, and wherein such stiffness orflexibility can be selectively or intermittently reduced through one ormore actions. For example, an assembly can be produced where a componentin a relaxed or natural state presses against a structural framework, inone example where a resilient tubular structure presses against astructural framework. In another example, a user can reduce a stiffnessor flexibility in an assembly by releasably inflating or enlarging atleast one of the tubular structures, which can reduce a stiffness orflexibility in at least part of the assembly.

These and other benefits will become more apparent with consideration ofthe description of the examples herein. However, it should be understoodthat not all of the benefits or features discussed with respect to aparticular example must be incorporated into a tubular structure,component or method in order to achieve one or more benefitscontemplated by these examples. Additionally, it should be understoodthat features of the examples can be incorporated into a tubularstructure, component or method to achieve some measure of a givenbenefit even though the benefit may not be optimal compared to otherpossible configurations. For example, one or more benefits may not beoptimized for a given configuration in order to achieve cost reductions,efficiencies or for other reasons known to the person settling on aparticular product configuration or method.

Examples of a number of tubular structure configurations and of methodsof making and using the tubular structures are described herein, andsome have particular benefits in being used together. However, eventhough these apparatus and methods are considered together at thispoint, there is no requirement that they be combined exactly asdescribed, used together in the exact combinations, or that onecomponent or method be used only with the other components or methods,or combinations as described. Additionally, it will be understood that agiven component or method could be combined with other structures ormethods not expressly discussed herein while still achieving desirableresults.

Catheters are used as examples of a tubular structure that canincorporate one or more of the features and derive some of the benefitsdescribed herein, and in particular vascular catheters. Catheters usedfor navigation and for support for other components in vessels have anumber of configurations, and such catheters can benefit from one ormore of the present inventions. Tubular structures other than catheterscan benefit from one or more of the present inventions.

As used herein, “substantially” and “approximately” shall mean thedesignated parameter or configuration, plus or minus 10%.

A lumenal or tubular structure can be incorporated into a number ofdevices, which may include apparatus and methods for varying thestiffness or flexibility of, or support provided by, such lumenal ortubular structure. The present examples described herein relate tolumenal or tubular structures for catheters, for example catheters fortraversing vasculature, including human vasculature. However, it isunderstood that the components and assemblies described herein can beused in a variety of structures and applications, including cathetersfor other applications, and other lumenal or tubular structures. Thepresent examples will include vascular catheters, but other structuresare applicable as well.

In one example of a lumenal or tubular structure (FIGS. 1-7), a catheterassembly 100 includes a catheter having a shaft 102. The catheterassembly 100 is configured to be sufficiently flexible to transit humanvasculature. The catheter assembly further includes a catheter hub 104.The catheter hub can take a number of configurations, and may be used toreceive and provide a number of structures and components and/or fluidsin the use and application of the catheter, and may be used with anumber of other instruments and/or components as would be understood toone of ordinary skill in the art. In the present example, the catheterhub includes an inflation or injection port 106 for receiving aninjection or inflation device, in the present example denominated assyringe 108 having a syringe body or barrel 110 and plunger 112, forexample for injecting and withdrawing fluid from or into the barrel 110.The syringe will be used to hold and inject or withdraw saline into orfrom the catheter hub 104 or lumen (in the example of FIGS. 8-9described more fully below). The syringe is mounted or secured in theinflation port 106 in a conventional way.

The catheter hub 104 includes a main body 114 extending longitudinallyand defining in part a main axis of the catheter hub, at the proximalportion of the catheter. The catheter hub body 114 includes an internalwall defining a bore 116 extending from a proximal end 118 of thecatheter hub to a distal end 120 of the catheter hub, and is configuredin a conventional manner for receiving devices and materials, and mayreceive in the present example a dilator 122 as illustrated. The dilatorcan be omitted, or replaced by a cover or by other components. In thepresent example, the dilator 122 includes a dilator hub 124 mounted onor secured to the proximal end 118 of the catheter hub, and a dilatorshaft 126 extending longitudinally of the catheter hub inside the wall116 and within the catheter shaft 102. In the present example, thedilator shaft 126 extends through a distal end portion 128 of thecatheter shaft and includes a dilator tip 130. In the present example,the dilator tip extends beyond a distal end surface 132 of the cathetershaft, for example a distance typical for catheter and dilatorassemblies. The dilator 122 is a conventional dilator, configured foruse with a catheter such as any of those described herein. In oneexample, the dilator is configured for receiving a guidewire or otherguide device (not shown) through the central lumen of the dilator.

The inflation port 106 includes an internal wall 134 defining a boreextending to the central bore 116 of the catheter hub. The inflationbore 134 is in fluid communication with the central bore 116, and fluidfrom the inflation port 106 can flow into and out of the central bore116 around the dilator shaft with the operation of the syringe 108, aswell as under the influence of any other forces or influences in thedesign of the catheter. An interference fit between the dilator distalend and the catheter shaft distal end keeps fluid in the central bore116.

The catheter shaft 102 includes a lumenal member, in the present examplea tubular member 150. A proximal portion 152 of the tubular member 150is mounted, secured and sealed in the distal portion 120 of the catheterhub in a conventional manner. The tubular member extends longitudinallyfrom the catheter hub to the distal end portion 128 of the cathetershaft, and specifically terminates in the present example at the distalend surface 132. The tubular member is formed so as to be sufficientlyflexible for transiting human vasculature and body lumens, includingcardiac, peripheral, and cerebral vasculature, which can be tortuous.The tubular member 150 in the present example has a substantiallycircular cross-section, but can have other cross-sectional profiles. Thetubular member is substantially coaxial with the central axis of thecatheter hub 104 when in the shape as illustrated in FIGS. 1 and 2.

The tubular member 150 is substantially cylindrical over substantiallyits entire length. The tubular member also has a substantially uniformwall thickness over substantially its entire length, for example0.003″-0.020″, and it also has a substantially uniform inner diameter,for example 0.025″-0.100″, over its entire length from inside thecatheter hub up to just proximal of the distal end portion 128, which isdescribed more fully below. However, it is understood that other tubulargeometries can be used, and the catheter shaft can be formed with othercross-sectional profiles. Alternatively, the catheter shaft 102 can haveother constructions and geometries than those described herein, and suchother constructions and/or geometries may include lumens, as desired,for example for passage of apparatus or fluids, such as guide wires,tubular devices, instruments, saline, contrast, and other devices andmaterials.

The tubular member 150 is formed from a suitable material, which may bedetermined by the intended application. In the present examples, thetubular member 150 is formed from an elastomeric material conventionalfor vascular catheters, for example PEBA, polyurethane, or similar. Theinternal and external surfaces of the tubular member are configured tohave the desired finishes for their intended purposes. In the presentexample, the outside surface 154 (FIG. 3) permits easy movement throughother devices and through vasculature, as necessary. The inside surface156 permits fluid flow within the tubular member and easy movement ofthe dilator shaft 126 and any other devices or materials as desired,such as interventional devices/instruments.

In the illustrated example, the tubular member 150 includesstrengthening elements. In the present example, the strengtheningelements include one or more helical coil structures 158 (FIGS. 3 and4). In the present example, the helical coil 158 is a single continuoushelical coil extending from inside the catheter hub 104 to a pointadjacent the distal end portion 128 of the tubular structure. Thehelical coil can take the form of conventional reinforcement forconventional catheter tubes, and may be stainless steel, for example 304or 316 stainless steel, with a diameter of 0.001″-0.007″, and a pitch of0.003″-0.020″. Furthermore, the coil may be formed from a wire with anon-circular shape in cross section, such as a rectangle or oval crosssection. The coil can be formed from other materials, with other coiland strand diameters and/or with other pitches, to provide the desiredstrength, reinforcement and/or stiffness. Other strengthening devicescan be used, either alternatively or additionally. For example, braidstructures can be used. In the present example, the strengtheningelements are embedded in or coextruded with the tubular member 150, forexample as would be conventional.

The tubular member 150 extends distally to the distal end portion 128,where the coil 158 terminates. The elastomeric tubular member continuesdistally at a converging portion 160, which then terminates at acylindrical or annular wall portion 162. The distal end portion 128 isformed with a diameter so as to provide an interference fit with thedilator tip 130, both of which are configured to provide the desiredinterference fit.

The tubular member 150 geometry and structure in the present exampleextends uninterrupted from the proximal to the distal end portionsexcept for one or more apertures or fluid openings 164 (FIGS. 3-4). Theapertures 164 extend completely through the tubular wall between strandsof the coil and provide a fluid path between the inside and the outsideof the tubular member at a location of the openings, which in thepresent example are within an outer tubular member described more fullybelow. The fluid openings allow fluid to pass from the lumen within thetubular member 150, for example fluid from the inflation port 106, to acavity or recess or balloon outside the tubular member 150. In thepresent example, there are two fluid openings through the wall of thetubular catheter member.

Use of fluid to expand and/or contract the volume of a cavity containinga structural support element allows changing conditions of the tubularstructure. For example, inflation and deflation or reduction in pressureor application of vacuum can change a stiffness or flexibility of astructure. In one example, inflating a cavity containing a structuralsupport element can increase the flexibility of the catheter in the areaof the structural support element, and reducing the pressure, applyingvacuum or allowing deflation of the cavity can decrease the flexibilityof the catheter. In this way, the catheter can have a selectiveadjustability of its stiffness or flexibility.

The configuration of the tubular member 150, as the inner layer or innertubular element, can be configured in a number of ways. Flexibility canbe enhanced along the length, including in the distal portion of thetubular element, by changing the durometer of the material as a functionof its length, and/or adjusting the wall thickness of the tubular memberas a function of length or distance from the catheter hub. Alternativelyand/or additionally, the reinforcement can be modified as a function ofdistance from the catheter hub, for example by changing the geometry orthe spacing of the material. In the example of a helical coil, the pitchof the coil can be changed, or the diameter of the coil or strandelement embedded in the tubular member. The reinforcement material canbe metal or non-metal, and may be stainless steel, nitinol, polymericfiber, metallic wire with a radio opacity property, tantalum, tungsten,or alloys of these materials or other materials.

The catheter 100 further includes an adjustable member outside of thecatheter tubular member 150, extending over at least a portion of theouter surface of the tubular member 150. In the area of the adjustablemember, the catheter tubular member 150 is an inner tubular memberrelative to the outer adjustable member. In some configurations, theadjustable member is used to selectively establish or change aflexibility or stiffness of a portion of the catheter, for example theportion of the catheter around which the adjustable member ispositioned. The adjustable member can be used to sandwich one or moreunderlying components within an envelope, cavity or area over or aroundwhich the adjustable member extends. The adjustable member can be usedto increase surface areas of contact between adjacent elements, and toestablish or increase internal forces that must be overcome to move orchange a geometry of a portion of the catheter. The adjustable membercan also be used to effectively separate itself from a portion or all ofan underlying component, which may allow separation of additionalcomponents from each other, and which may also allow positionadjustments or other adjustments of one or more underlying components.The adjustable member can be configured to be normally in a firstcondition or normally in a second condition (for example having a memorycharacteristic), for example normally producing contact with underlyingcomponents or normally separating from underlying components, ornormally applying pressure or normally released from applying pressure.Alternatively, the adjustable member can be configured to remain in agiven state until acted upon, for example without any memorycharacteristic. In the examples described herein, the adjustable memberis configured to be normally in a collapsed, reduced or application modewhere pressure or force is applied by the adjustable member to one ormore underlying components. The adjustable member is adjusted bypositive action to change the adjustable member from its collapsed,reduced or application mode at least in part, for example to reduce asurface area of contact between the adjustable member and an underlyingcomponent. In the present examples, the adjustable member is movableradially. Also in the present examples, the adjustable member appliespressure to an underlying component along the entire length of theunderlying component substantially simultaneously.

An example of an adjustable member (FIGS. 1-9 and 11A-B) is tubularmember 200. In the present example, the tubular member 200 extends overa portion of the catheter shaft 102. The tubular member 200 forms anouter tubular member (outer tube) to the extent that it is outward ofthe adjacent portion of the catheter shaft 102. However, it isunderstood that one or more other components can be outward of the outertubular member 200. A proximal end 202 of the outer tube is secured toan adjacent portion of the catheter tubular member 150,circumferentially around the entire portion of the proximal end 202 ofthe outer tube. The proximal end can be sealed, welded, bonded, forexample thermally or adhesively, or otherwise secured to the outersurface of the catheter tubular member 150, for example in a mannersimilar to concentric catheter tubes may be secured to each other inconventional catheters. With the present outer tube, the outer tube issecured to the catheter tubular member 150 at both ends of the outertubular element in such a way that the junction can withstand expectedinternal fluid pressures developed between the outer tubular member andthe catheter tubular member 150.

The outer tube 200 extends distally from the proximal end portion 202over the catheter tubular member 150 to a distal end portion 204 of theouter tubular member, surrounding the distal end portion 128 of thecatheter tubular member 150. The distal end portion 204 is sealed,welded, bonded or otherwise secured to the adjacent distal end portionof the catheter tubular member in the same manner as for the proximalend portion 202. The outer tube 200 forms between the proximal anddistal end portions a cavity, envelope or annular space 206 between theinside surface 208 of the outer tube 200 and the opposite or facingouter surface 154 of the inner tubular member 150. The cavity 206 formsin the present examples a balloon which can be enlarged or inflated as afunction of the flexibility and strength of the outer tubular member200. In some configurations, the adjacent portion of the inner tubularmember may also be sufficiently flexible to provide a measure ofadditional inflation or enlargement, inwardly toward the central axis ofthe catheter, but the present configurations have the inner tubularmember 150 with the embedded coil 158 such that the wall of the innertubular member does not change diameter significantly under thepresently contemplated pressures within the cavity 206, and remains aconstant diameter before, during and after inflation or enlargement ofthe outer tubular element and an before during and after deflation orfull collapse of the outer tubular element.

In the present example, the outer tube 200 is a monolithic structure,and is formed from a material that is flexible and can increase indiameter (i.e., increase in diameter where the outer tube issubstantially cylindrical or circular) upon application of an internalpressure (for example between approximately 1-200 psi) between the outertube 200 and the inner tube 150. The outer tubular element serves as aballoon that can expand outwardly upon application of an internalpressure, for example pressure developed by a fluid, in one example arelatively incompressible fluid. The outer tubular element 200 isconfigured to have a maximum expandable diameter under normal operatingconditions for example by selecting a material that can inherentlyexpand or stretch to a selected or preferred diameter and maintain thatdiameter even with possible expected higher pressures.

The outer tubular element 200 in the present examples is formed frompolyurethane, and has a wall thickness of approximately 0.003″. In thepresent examples, the outer tubular element 200 has a relaxed internaldiameter when originally formed and before assembly on the catheter ofapproximately 0.100″, when the other components inside the outer tubularelement are dimensioned as described herein. It has an expected inflatedinternal diameter of 0.118″. The material is preferably abrasionresistant, and highly resistant to puncture. The outer tubular element200 in the present examples has a structure similar to balloon cathetersbut without any folds or creases, and can be produced in a mannersimilar to balloon blow molding processes. In the present example, theouter tubular element 200 is formed prior to assembly to be configuredto be normally collapsed when assembled in the catheter. Once installedand if the outer tubular member is enlarged or inflated, the material ofthe outer tubular member is configured to produce an elastic recoil whenthe pressure is reduced or removed. The outer tubular member can bemodified in a number of ways, but in the present examples is configuredto be uniform throughout its length. In other examples, the outertubular member can be configured to have different characteristics atdifferent places along its length, for example based on durometer,thickness, the original or relaxed or recovered shape and/or diameter,material and thickness, and circumferential configuration. However, inthe present examples, the response of the outer tubular member toinflation or enlargement pressure from an internal fluid is relativelyuniform throughout the outer tubular member, and reaches a predeterminedouter diameter, which is maintained even with higher pressures untilpressure is removed and the outer tubular member deflate, retracts orreturns to the structural support element. In this way, inflation orexpansion of the outer tubular element allows disengagement of layerswithout overstretching the outer tubular element. The outer tubularelement can be configured to have a non-linear pressure versus diameterrelationship such that the diameter of the outer tubular element canincrease with pressure up to a predetermined diameter, after which nofurther expansion occurs.

In the present examples, the catheter tubular member 150 and the outertubular element 200 form nested tubular structures which are concentric,and together they define a cavity. Alternatively, they can be other thanconcentric, and they can have geometries other than cylindrical orcircular cross-sections.

Lumenal structures and tubular structures, including the tubularcatheter 100 can include support structures, for example medial orintermediate support structures, that can provide stiffness to thelumenal and tubular structures, and in the present examples, can provideselectable or variable adjustable stiffness or flexibility to thelumenal and tubular structures. The support structure can be placed theentire length or at a number of locations along the length of thelumenal and tubular structures, and in the present examples, the supportstructure is positioned adjacent the distal end of the catheter. In thepresent example, the support structure is a medial member that is placedbetween the lumenal and tubular structures. In one configuration of thesupport structure and the lumenal or tubular structure, the supportstructure can have an adjustable stiffness or modifiable stiffnessconfiguration, which configuration can be affected by its geometry andhow it is combined with the lumenal or tubular structure. In oneconfiguration, the support structure is sandwiched or interposed betweentwo structures, one or both of which may be adjustable relative to thesupport structure to change the stiffness of the assembly. In that oranother configuration, the support structure has surfaces contacting oneor more adjacent surfaces in the lumenal or tubular structure, whichcontact results in frictional forces if the support structure bends orotherwise changes its configuration. The frictional forces resist theconfiguration change, contributing at least in part to increasedstiffness or decreased flexibility of the assembly, for example in thearea of the support structure.

The support structure can take a number of configurations, and whenplaced over a lumenal or tubular structure, the support structure canalso be a tubular support structure. The support structure can take theform of a tubular mesh, including a non-random mesh configuration, atubular skeletal structure, a tubular framework, a tubular braid, astent, for example such structures as medically implantable stents, andother structures. “Non-random” as used herein in the context of astructural support element is one that includes elements between theends of the structural support element that were configured in aselected or controlled way. In some configurations, for example wherethe support structure is a tubular mesh, skeletal structure, frameworkor stent, elements making up the support structure can have a relativelyhigh degree of interconnectedness, while still providing some degree offreedom of movement. In contrast to stents, however, the present supportstructure does not expand radially or extend longitudinallysubstantially once the catheter is assembled, other than what mightoccur on bending of the catheter and therefore the support structure. Inthe art of stents, a relatively low degree of interconnectedness wouldbe termed an open cell configuration, and a relatively high degree ofinterconnectedness would be termed a closed cell configuration, or onetending more toward a closed cell configuration than an open cellconfiguration. Higher levels of interconnectedness in a tubular mesh,skeletal structure or framework may have more interconnections betweenelements than fewer interconnections. Interconnectedness contributes toan ability or inability of the support structure to move or change itsgeometry, with movement being easier with fewer interconnections, andmore difficult with more interconnections.

In addition to the inherent characteristics of the support structure toallow or resist movement or changing geometry, interactions of thesupport structure with adjacent surfaces also affects resistance tomovement or changing geometry. For example, larger surface areas ofcontact between the support structure and adjacent surfaces give rise tofrictional forces to a greater extent resisting movement or geometrychanges than smaller surface areas of contact. Support structures havinglarger numbers of components with surface areas that can contact theadjacent surfaces will exhibit higher resistance to geometry changes ormovement than ones having smaller numbers of components, all otherthings being equal. Similarly, the surface characteristics of thecomponents of support structures may also affect the resistance togeometry changes or movement. For example, surface textures or surfaceedges may contribute to higher frictional forces when in contact withadjacent surfaces that may resist geometry changes or movement. In oneconfiguration, described more fully herein, a surface of the supportstructure facing an adjacent surface may be configured to include raisedstructures, for example protrusions or raised areas or outwardlyextending structures (outwardly of the surface), or a combination ofraised and recessed areas, which may contribute to higher frictionalforces when in contact with the adjacent surface to help resist geometrychanges or movement. For example, one or more facing surfaces of thesupport structure may include one or more raised structures extendingoutward from the facing surface a distance and having an element orsurface area that may come into contact with the adjacent surface, and araised structure may have a number of configurations such as pointed,extended or distributed, or other surface configurations that cancontact the adjacent surface.

The catheter 100 includes an intermediate or medial member in the formof support structure 300 (FIGS. 2-9). In the present example, the medialmember is solely the support structure 300 in the form of at least onemonolithic structure having a tubular shape made up of componentelements such as spars, struts, or linear or curving limbs 302interconnected with each other with open space 303 in between to formthe support structure 300, and the cross sections of FIGS. 2-9 showcross sections of elements of the support structure 300 not to scalewith the pitch of the coil 158, with the understanding that the exampleof the support structure 300 is shown in and described in more detailwith respect to FIGS. 10-13. The support structure is athree-dimensional configuration of spars, struts, or linear or curvinglimbs and intermediate cavities or openings whose configuration can beselectively adjusted or changed and releasably fixed in place asdesired. The adjacent structures can be selectively coupled anddecoupled to provide support or tracking as desired. In the presentexamples, three components are mechanically or frictionally decoupled toa greater or lesser extent to allow selective changing or adjustment ofthe configuration of the support structure, after which the threecomponents can be re-coupled, for example mechanically and withincreased surface areas of contact for frictional engagement.

In the present example, the support structure 300 is positionedintermediate the tubular member 150 and the outer tubular member 200, inthe cavity or annular void 206 formed between the inner tubular memberand the outer tubular member 200. Also in the present example, thesupport structure 300 extends substantially from the proximal endportion 202 of the outer tubular element 200 to the distal end portion204, and the configuration of the support structure is substantiallyconsistent over the length thereof. However, the support structure canbe configured to have different configurations as a function of axialposition and/or circumferential position. The support structure 300 canbe secured to the outer surface 158 of the inner tubular member 150, forexample by tacking, adhesive, or other means, such as at one or severalendpoints at the proximal and distal ends of the support structure. Suchsecurement may assist in assembly, and such securement can be eliminatedprior to final assembly if desired. Conversely, flexibility of thedistal portion of the catheter can be reduced as a function ofsecurement of the structural support 300 to the inner tubular member150, axially and/or circumferentially. However, such reduction generallywould not be reversible, and would decrease the baseline flexibility orincrease the stiffness of the distal portion of the catheter and itcould be difficult to increase the flexibility above the baseline orreduce the stiffness.

The components of the structural support 300, such as the limbs 302, canhave a number of geometries. In the present example, each limb 302 has asubstantially rectangular cross-section with a long axis parallel to themain axis of the catheter, and short axis perpendicular thereto. Havingthe long axis parallel increases the surface area of each limb that cancontact an adjacent surface 158 of the inner tubular member and theinner surface 208 of the outer tubular member 200. However, othergeometries can be used. In the present example, each limb 302 of thesupport structure 300 is illustrated in FIGS. 4 and 4A as being slightlyspaced outward from the outer surface 158 of the inner tubular element150. The support structure can be configured to have a larger insidediameter in a relaxed state than an outside diameter of the outersurface 158, which may then produce limited surface contact between thestructural support 300 and the inner tubular member 150 when firstassembled. Alternatively, the support structure can be configured tohave an inside diameter in the relaxed state comparable or approximatelythe same as the outside diameter of the outer surface 158, so thatgreater surface contact occurs between the structural support and theinner tubular member. In another alternative, the structural support 300can be configured to have a smaller inside diameter in the relaxedstate, for example through an inherent bias in the support structure, tohave a higher surface area of contact with the inner tubular element inthe relaxed state. Higher surface area of contact promotes stiffness,relative to lower surface area of contact between the support structure300 and the inner tubular element 150.

As illustrated in FIG. 4, each limb 302 of the structural support 300has a relatively defined set of corners or angular transitions 304 fromone side to an adjacent side. The corners 304 are exaggerated in theirsharpness, but the curvature of the transition between surfaces around aperimeter of a limb can affect frictional forces arising through contactbetween a limb and an adjacent surface, either with the outer surface154 of the inner tubular element or with the inner surface 208 of theouter tubular element. The quantity or extent and the quality of theedge contact between limbs and their adjacent surfaces will contributemore or less to the stiffness or flexibility of the combination. Allother things being equal, sharper or more angular transitions betweensurfaces produce higher frictional forces and increased stiffness ordecreased flexibility. Therefore, a non-round limb profile on thestructural support 300 can enhance the stiffness or reduce theflexibility of the distal portion of the catheter when the structuralsupport contact the adjacent surfaces. Similarly, textures on surfacesof the support structure contacting adjacent surfaces of the tubularelements can also increase friction and stiffness or decreasedflexibility. For example, a nitinol structural support 300 that is notelectro-polished may enhance the stiffness or reduce the flexibility ofthe distal portion of the catheter as a result of surface contact withthe adjacent surfaces of the inner and/or outer tubular elements.

The structural support element can be formed from a number of materials,including stainless steel, nitinol, polymeric materials, and othersuitable materials. The structures can have cross sectional geometriesthat are smooth or angular, and may be finished or unfinished, etched ornot, abraded or not (e.g., grit blasting), and for example with nitinol,electropolished or not. A structural support element such as a stentwill be configured to have a structure, material, and characteristics ofsuch a stent, such as extends used for medical implantation.

The illustrations of catheters in FIGS. 1-9 show the catheter shaftextending straight, in what is considered a neutral configuration. Insuch a configuration, and as can be seen in FIG. 4, the outer surface158 extends axially substantially straight, and the adjacent surfaces ofthe limbs 302 of the support structure 300 extend substantially parallelto the outer surface. Relatively little frictional engagement occurs insuch a configuration between the corners 304 and the outer surface 154until such time as the catheter bends. When the catheter bends, theconcave portion of the bend may have relatively higher contact andfrictional engagement with the corners 304 of the adjacent limbs, forexample at both corners of a limb, whereas in the convex portion of thebend, fewer of the corners 304 might contact the adjacent outer surface154.

The outer tubular element 200 is relatively more flexible than the innertubular element 150. In a configuration where the outer tubular element200 is constricted, deflated, or otherwise pressed against the supportstructure 300, the flexibility of the outer tubular element 200 allowsthe inner surface 208 to somewhat conform to the adjacent surface of thesupport structure. Specifically, the inner surface 208 extends over alimb 302 and curves or bends around adjacent corners 304 it contacts.Additionally, the outer tubular element 200 extends into the gaps orspaces 210 between adjacent limbs of the support structure.Consequently, possible movement of the limb 302 to the left as viewed inFIG. 4A (or outward toward the outer tubular element 200) will tend toincrease the frictional engagement between the corner 304 and theadjacent surface 208A, increasing the resistance to movement of thelimb. Similar actions occur with other limbs and their adjacent surfacesof the outer tubular element, thereby accumulating forces resistingmovement, and also increasing the stiffness or decreasing theflexibility of that portion of the catheter. Any increase in frictionalengagement between limbs of the structural support 300 and adjacentsurfaces of the outer tubular element 200 and/or inner tubular element150 as a result of bending of the catheter will depend on the locationand direction of the bending.

Resistance to bending or stiffness in the distal portion of the cathetercan be reduced by reducing the amount of surface area of contact betweenone or more limbs 302 of the support structure 300 and one or moreadjacent surfaces. The extent to which such contact can be reduced maydepend on which surface or surfaces release or move out of contact withthe support structure, and how many surfaces release or move out ofcontact. In one configuration, contact between the support structure andone or more adjacent surfaces may occur simply by moving the catheter,so that the adjacent surface 154 of the inner tubular structure 150and/or the adjacent surface 208 of the outer tubular structure 200 slideor slip over the respective limb surface. In another configuration,including those illustrated herein, one or both of the adjacent surfacesof the inner tubular structure and the outer tubular structure becomeseparated from the respective surface or surfaces of the supportstructure, thereby reducing or eliminating surface contact therebetween,and thereby reducing or eliminating the contributions of those surfacesresisting movement of the catheter.

In one example (FIGS. 5-6), the outer tubular element 200 can bereleased, moved away or separated from one or more adjacent surfaces ofthe support structure 300. For example, fluid in the syringe 108 can beinjected into the lumen 134 of the inflation port, and into the interiorlumen of the catheter hub and the catheter. As the pressure in theinterior of the catheter increases, fluid flows through the apertures164 into the annular cavity 206 between the inner and outer tubularmembers. With the increase in pressure in the annular cavity, the outertubular element expands or enlarges, and the interior walls 208 begin tomove radially outward, and out of contact with, or mechanically andfrictionally disengage from, the adjacent surfaces of the structuralsupport 300. The amount or extent of disengagement will be a function ofthe pressure, and the location or locations of the apertures 164. In theexample of an incompressible fluid and sufficient apertures 164distributed along the cavity 206, substantially all of the outer tubularelement will release from the structural support 300, bothcircumferentially and longitudinally. When all or any portion of theouter tubular element releases from adjacent surfaces of the limbs 302,the flexibility of the catheter in the area of the outer tubular elementcommensurately increases and the stiffness commensurately decreases.Conversely, as more of the outer tubular element comes into contact withadjacent surfaces of the limbs 302, the flexibility of the catheter inthat area commensurately decreases and the stiffness commensuratelyincreases.

In the example illustrated in FIGS. 5-6 and other examples herein,variable stiffness is incorporated in a portion of a catheter. Forexample, when the outer tubular element is in a relaxed state, such aswhen excess fluid is removed from the annular cavity 206 and thecatheter lumen, such as by withdrawing the plunger 112 on the syringe108, or by applying vacuum, that portion of the catheter has increasedstiffness. Conversely, when the outer tubular element is expanded orinflated, such as by injection of fluid into the catheter lumen and thecavity 206, the portion of the catheter has decreased stiffness.Therefore, in the examples herein using inflation and deflation,inflation and deflation can be used to affect stiffness or flexibilityof the tubular element. In the present example, inflation increasesflexibility. Similarly, a relaxed or natural state of the outer tubularelement decreases flexibility and provides a stiffer construction.Additionally, the ability to increase or decrease stiffness orflexibility depends in part on the encapsulated or encased structuralmember 300, which is independent of structures outside the outer tubularelement or structures inside the dilator. The intermediate or medialstructural support 300 is sandwiched between opposing continuoussurfaces, one or both of which are movable, for example radially, suchas where the outer tubular element 200 can expand radially outwardrelative to the structural support 300.

In the present examples, the outer tubular element wall is movable withfluid pressure, outward with increasing fluid pressure, and inward withdecreasing fluid pressure. Increasing the fluid pressure separates orwidens the spacing between the facing walls of the outer tubular elementand the inner tubular element, 208 and 154, respectively. Decreasing thefluid pressure decreases the spacing between the facing walls of theouter tubular element and the inner tubular element, and eventuallybrings the outer tubular wall into contact with one or more limbs of thestructural support 300. As pressure is removed, the outer tubularelement applies pressure to the structural support 300 squeezing thestructural support between the outer and inner tubular elements, therebychanging the mechanical properties, stiffness and flexibility of thatportion of the catheter. Where fluid is used to inflate the outertubular element, it can be seen that the structural support 300 is in aclosed fluid system, and in a cavity that is closed except for fluidcommunication with a source of fluid for fluid pressure. Having thesupport structure in an enclosed cavity in the catheter provides morepredictability in the adjustability of the stiffness or flexibility ofthe catheter. Additionally, when the outer tubular element is formedfrom a material and configured on assembly to be resiliently biased inthe direction of the structural support member, the resiliency of theouter tubular element helps to maintain the sandwich or application ofpressure on the support structure when pressure is reduced or removed.Flexibility of the catheter can be adjusted by changing how thestructural support element 300 is captured between the layers orconcentric tubular elements of the outer tubular element 200 and innertubular element 150. Flexibility can be adjusted by manipulating fluidin the fluid system of the catheter lumen and the cavity 206, and thefluid can be used to separate or increase the spacing between theconcentric tubular elements. Similar effects can be achieved by reducingfluid pressure in the cavity, for example where the outer tubularelement has a relaxed or unbiased configuration, making little or nocontact with the support structure. By reducing pressure in the cavity206, the outer tubular element can be drawn into further contact withmore surface area of the structural support, thereby increasing thesurface area of contact and the rigidity or stiffness of that portion ofthe catheter. Alternatively in the examples illustrated herein where theouter tubular element is configured in its natural or relaxed state tobe pressing against the structural support element, for example where inthe relaxed state the outer tubular element has an inside diameter lessthan an outside diameter of the structural support element, the naturalconfiguration of the assembly is to have the outer tubular elementpressing against the structural support element absent increased fluidpressure in the cavity 206. Additionally, the assembly can be configuredso that fluid pressure reduces naturally if no active pressure is beingapplied to the syringe 112 by a user.

The catheter assembly is used so that the catheter 100 can be positionedin a desired position, for example within the vasculature, for exampleby using a guide device to guide the catheter into a desired locationand position. For example, a guidewire (not shown) extends into thecentral lumen of the dilator and is guided into the appropriatevasculature, and the dilator and catheter with the outer tubular elementinflated or enlarged is passed along the guidewire until positioned asdesired. Once in position, the outer tubular element is deflated orreduced to fix the catheter geometry in position. The dilator 122 isthen removed, and the remaining catheter with the adjustable flexibilityelement fixed remains in place for subsequent procedure. As shown inFIG. 7, the dilator has been removed and the syringe 108 has beenremoved from the injection port 106. The catheter is then ready toreceive an intervention device, material or other component through thecatheter hub 104. When the procedure is complete, fluid is reintroducedinto the lumen either with the intervention device in place or adilator, a syringe attached to the injection port 106 and the outertubular element 200 inflated to allow removal of the catheter 100.

In an alternative embodiment of a catheter (FIGS. 8-9), a catheter 100Ahas an outer tubular element 200 enclosing a structural support 300, andhas the structures and functions described above with respect to theexample of FIGS. 1-7 except as discussed herein. In the present example,the catheter 100A includes a catheter shaft 102A identical to thecatheter shaft 102 but for omitting the apertures 164, but for theproximal portion of the catheter shaft extending further into thecatheter hub 104A beyond the opening of the injection port 106, andexcept for one or more inflation lumens 170. The construction, geometryand dimensions of the exemplary catheter shaft 102A is substantiallyidentical to that for catheter shaft 102 except that the catheter shaftincludes the inflation lumen 170 defined by an interior wall 172extending from the inflation lumen 134 in the catheter hub 104A to theproximal portion 202A of the outer tubular element 200. The inflationlumen 170 has an interior lumen configured to permit the desiredinflation of the outer tubular element, which allows the catheter to beused without a dilator for inflating or enlarging the outer tubularelement 200. The proximal portion 202A is sealed around the cathetershaft and the distal portion of the inflation lumen 170, and withstandsany fluid pressure expected within the lumen and the cavity 206 of theouter tubular element. The proximal portion of the catheter is supportedby and sealed in the catheter hub 104A as would be done in aconventional catheter. The catheter is shown in FIG. 8 having the outertubular element 200 deflated or in its collapsed configuration, pressingagainst the structural support 300, sandwiching or pressing thestructural support 300 between the outer and inner tubular elements.Injecting fluid into the lumen 170 and increasing the pressure in thefluid system from the injection port 106 through the lumen 170 and intothe cavity 206 within the outer tubular element 200 enlarges or inflatesthe outer tubular element 200, so that pressure is no longer applied topart or, in the illustrated example, all of the structural supportelement 300, and to reduce the stiffness and increase the flexibility ofthat portion of the catheter (FIG. 9).

The structural support element 300 in the present example includes arepeating pattern (FIGS. 10-13). FIG. 10 shows the structural supportelement 300 extending along and around the adjacent portion of the innertubular element 150 from a first end 306 to a second end 308. Becausethe structural support element is formed from a tubular mesh design, thefirst and second end portions are terminations of the pattern inbetween, and are not terminated with extra structures added to the endportions that are not present in the interior pattern.

The structural support element which has a repeating pattern can havethe repeating pattern isolated into repeating groups or cells, while itis understood that a structural support element that does not have arecognizable repeating pattern will have a more complex structure thatmay not be amenable to identification of repeating groups or cells. Thepresent support structure 300 (FIG. 12) includes a cell 310, which inthe present example repeats circumferentially to provide six cells, andin the example illustrated in FIG. 10 repeats longitudinally to provide11 cells plus a terminal boundary structure, which equates toapproximately a half cell, depending on how the support structure isproduced. Because the support structure is to be used in a catheter inthe present example, it is desirable to exclude any free-ended limbs302. In the illustrated examples, each limb terminates at both ends atrespective ones or more other limbs.

In the structural support element 300, each cell 310 includes a firststrut 312, which in the present configuration is alongitudinally-extending strut that extends longitudinally of thetubular support structure, and parallel to the axis of the inner tubularmember 150. As shown in FIG. 10, the support structure and the tubularinner element 150 are concentric and coaxial over the length of thestructural support element 300. The cell 310 also includes parts ofadjacent longitudinal struts 312A and 312B. The longitudinal struts 312extend parallel to each other, and are distributed circumferentiallyabout the tubular support structure. In the present configuration, thelongitudinal strut 312 is offset both circumferentially and axiallyrelative to the adjacent longitudinal struts 312A and 312B.

Each longitudinal strut includes a first end 314 and a second end 316.Each of the first and second ends are joined or coupled to a pair ofserpentine struts extending from opposite sides of the longitudinalstrut. The first end 314 is joined or coupled to a first serpentinestrut 318 on one side of the longitudinal strut, and to a secondserpentine strut 320 on an opposite side of the longitudinal strut fromthe first serpentine strut 318. The first end 314 of the longitudinalstrut forms a node at which three struts join or converge. Similarly,the second end 316 of the longitudinal strut 312 is joined or coupled toa third serpentine strut 322 on one side of the longitudinal strut, thesame side as the first serpentine strut 318, and a fourth serpentinestrut 324 on an opposite side of the longitudinal strut from the firstand third serpentine struts 318 and 322. The first and second serpentinestruts extend away from the longitudinal strut 314 and toward the thirdand fourth serpentine struts, which also extend away from thelongitudinal strut 314 and toward the first and second serpentinestruts, respectively.

The opposite ends of the second and fourth serpentine struts are joinedor coupled at their respective ends to respective longitudinal struts312B and 312A, the ends of which form their respective nodes. The secondserpentine strut 320 is joined or coupled to a second end 328 of theadjacent longitudinal strut 312B, and the fourth serpentine strut 324 isjoined or coupled to a first end 330 of the adjacent longitudinal strut312A. A fifth serpentine strut 332 is coupled to the second end of thelongitudinal strut 312B, and to the first end of a longitudinal strut312′. A sixth serpentine strut 334 is coupled to the first end 330 ofthe longitudinal strut 312A, and to the second end of the longitudinalstrut 312′. Therefore, in the present configuration, a cell 310 includestwo longitudinal struts, as the outline is drawn formed from a fulllongitudinal strut and two halves, and the cell includes four serpentinestruts formed from two complete serpentine struts and the sums of fourpartial serpentine struts. Each cell includes four nodes, and each nodeis the junction of three struts. As can be seen in the illustratedexample, all struts are coupled or joined to at least two other struts,and the longitudinal struts are coupled to four serpentine struts, andeach serpentine strut is coupled to two longitudinal struts. Thisarrangement provides a moderate degree of interconnectivity, allowsfree-form radial expansion and contraction (before the support structureis combined with any other structure), and allows free-form longitudinalexpansion and contraction. The amount of expansion and contraction isdetermined in part by the starting angle of an angle 336 when thesupport structure is first formed. For example, when the supportstructure is first formed with a relatively small angle 336, greaterradial expansion is permitted than radial contraction because thestarting angle is small. Conversely, when the first support structure isfirst formed with a relatively large angle, the remaining radialexpansion is less, and the available radial contraction is greater thanfor a smaller starting angle 336.

The structural support member 300 at any given transverse cross-sectionis configured to have at least two struts in the cross-section, and inmany designs will have at least three struts, as three points define aplane. In the exemplary structural support member 300, a transversecross-section will intersect at least six struts 312 (FIG. 11A). The sixlongitudinal struts 312 are distributed substantially uniformly aboutthe circular support member 300. Such a transverse cross-section can bevisualized in FIG. 12 at either of the lateral sides (as visualized inFIG. 12) of the cell 310. However, at other transverse cross-sectionsaxially along the structural support member, additional struts will bevisible, for example 12 when the transverse cross-section intersects anode such as 328, and for example 24 when the transverse cross-sectionintersects intermediate portions of the serpentine struts. Additionallyas would be seen in a transverse cross-section, the longitudinal strutsare different size from the serpentine struts, and have a largercross-sectional area. There are more of the smaller struts than thereare larger struts, and in the present example twice as many smallerstruts than larger struts in a given cell. As can also be seen in FIG.12, all of the struts are connected, and in the present exampleinterlinked or interconnected so that each strut is connected to atleast two other struts. Also as can be seen in FIGS. 10 and 12, nosingle longitudinal strut extends the entire length of the structuralsupport member without a bend or transition to another longitudinalstrut. Additionally, in the illustrated example, no single element ofthe structural support member, in the present example no single strut,extend the entire length of the structural support member without a bendor transition to another element/strut.

In the present examples of support structures, the support structuresare formed from solid tubular elements having a constant wall thickness(thereby providing a substantially constant thickness for all of thestruts) and laser cut in a manner similar to the formation of stents toform the tubular mesh illustrated in FIG. 10 or in FIGS. 16 and 17. Inthe example of the support structure 300, the angle 336 formed duringformation of the support structure may be a small acute angle, forexample as small as several degrees (1-2°), or a large acute angle, forexample as large as 85-89°. Larger angles (obtuse) are possible as welland provide structural support, but do not provide the same structuralsupport once incorporated into a catheter assembly as does theconfiguration of the support structure 300 having an acute angle 336when initially formed.

In the configuration of the structural support produced using thepattern shown in FIG. 12, the angle 336 is selected to be approximately8°. In the final assembled configuration of the structural support shownin FIG. 10, the angle represented by 336 is approximately 24° afterexpanding the support structure.

The support structure 300 in the present examples is formed from a solidtubular element having a wall thickness of 0.003 inch. The structuralsupport 300 is then formed by laser cutting, in a manner similar to thatused for forming stents, so that all of the struts have a thickness 338equal to the starting wall thickness of the solid tubular element. Inthe present example, the width 340 of the longitudinal strut isapproximately 0.004 inch, which is approximately twice as much as thewidth 346 of the serpentine strut, which is approximately 0.002 inch, inthe present example, and greater than the thickness, while the thicknessis approximately 0.003 inch, which is greater than the width 346 of theserpentine struts. Consequently, the longitudinal struts resist bendingmore than the serpentine struts. The geometry of the cells, the wallthickness of the struts, the width of the struts, and the angle 336contribute to determining the stiffness, flexibility or resistance tobending of the support structure, in free-form separated or apart fromthe catheter assembly. Such stiffness, flexibility or resistance tobending of the support structure is carried into the assembly in thecatheter, and will exhibit similar characteristics in the catheterassembly. The thicknesses and widths of the struts can be selected to bebetween approximately 0.0005 inch and 0.0100 inch. Additionally, thestiffness, flexibility or resistance to bending of the catheter assemblyin the area of the support structure 300 is determined in part by thestiffness, flexibility or resistance to bending of the support structureper se, as well as the engagement and interaction of the components ofthe assembly with each other, including surface areas of contact betweenthe structural support and adjacent surfaces. When such surface areas ofcontact are reduced or removed, such as by inflation or enlargement ofthe outer tubular element, the various contributions to stiffness,flexibility or resistance to bending are reduced but the inherentstiffness, flexibility or resistance to bending of the support structureper se remains. Therefore, the design or pattern of the supportstructure determines not only the stiffness, flexibility or resistanceto bending of the support structure per se, but also the contribution tothe stiffness, flexibility or resistance to bending of the catheterbased on the interaction of the support structure with adjacentcomponents. In the configuration described and illustrated in FIGS.10-13, the structural support member has cells with the surfaces facingthe outer tubular member wherein each cell has a facing surface area ofabout 0.00075824 in., and likewise with the surface of each cell facingthe inner tubular member. Also in the configuration illustrated in FIGS.10-13, each limb has an outer surface facing the outer tubular memberand an inner surface facing the inner tubular member where the inner andouter surfaces are relatively uniformly smooth or flat, for example asillustrated in FIG. 13, to the extent permitted by the manufacturingtechniques used for making the support member. Alternatively, asdescribed herein, the outer and/or inner surface of at least one limbmay be other than smooth, and may include discontinuities or otherconfigurations that form structures extending outward from a respectivesurface for engaging a respective adjacent structure to change therelative contribution to the stiffness, flexibility or resistance tobending of the assembly at least in the area of the outward extendingstructures.

The effect of interaction between the support structure 300 and anyadjacent components is affected in part by the radial position of thesupport structure. With a flexible inner tubular member 150 having aninside radius from the center R1 and an outside radius from the centerof R2, the support structure 300 will be on or closely adjacent theoutside surface 154 of the inner tubular element. In the presentexamples, the inside diameter of the support structure 300 isrepresented by radius from the center R3 which is substantially equal tothe radius R2, so that the support structure contacts the outsidesurface 154 of the inner tubular member. The outside radius R4 of thesupport structure 300 is then determined by the wall thickness of thesupport structure. Additionally, the inside diameter of the outertubular member 200 is represented by the radius from the center R5, andthe outside diameter is represented by the radius R6, both of which aregiven while the outside tubular element is enlarged or expanded orinflated. The maximum inside diameter of the outer tubular element in arelaxed or collapsed state corresponds to substantially R4, namely theoutside diameter of the support structure, and the maximum outsidediameter of the outer tubular element in the relaxed or collapsed stateis substantially R4 plus the wall thickness of the outer tubularelement. The minimum inside diameter of the outer tubular element whenin the collapsed or uninflated state will depend on the flexibility ofthe material of the outer tubular element, and the relative surface areaof the open areas between struts that will allow the material of theouter tubular element to extend between the struts. The radius values ofthe structural support 300 are set forth in the Table I below:

TABLE I R1 0.044 in. R2 0.055 in. R3 0.055 in. R4 0.058 in. R5 0.060 in.R6 0.063 in.

Resistance to bending in tubular structures such as catheters generallyoccurs on an outer surface of the tubular structure. As illustrated inFIG. 11A, the support structure and the outer tubular element arepositioned at the outer reaches of the assembly, and the mechanism inthe form of the structural support that is used in the present examplesto provide variable stiffness is located in the area of or on an outsidesurface of the inner tubular member, for example where the mechanicalproperties of the structural support can have a strong effect. Asillustrated in FIG. 11A, the structural support is in the area ofapproximately 95% of the maximum outer diameter of the catheter.Therefore, the effect of the structural support on the flexibility orstiffness of the portion of the catheter at which it is placed by havingit applied at outer areas of the catheter relative to the center axis,for example between 50% and 100% of the overall outside diameter of thatportion of the catheter. Additionally, the function of surface area ofcontact, such as between the structural support and the outer surface154 of the inner tubular member 150, and/or between the structuralsupport 300 and the outer tubular element 200, is improved bypositioning the structural support element at a higher radial positionthan a lower radial position, because the surface area availableincreases with the square of the radius. Therefore, placing thestructural support element outside the inner tubular element 150enhances the contribution of the surface area of contact and frictionalresistance developed between the structural support and any adjacentsurfaces.

FIG. 14 illustrates a portion of the structural support 300 in anapproximately neutral state, for example after assembly onto an innertubular element and formed into a catheter assembly, ready for usethough after some residual movement as not all of the longitudinalstruts 312 are precisely parallel and the serpentine struts, labeledgenerically as 348, have adjusted accordingly. The longitudinal strutsare not in compression or tension and are substantially regularly spacedfrom each other, and the serpentine struts 348 also are not in tensionor compression, but such condition will depend on the initial magnitudeof the angle 336 (FIG. 12) when the support structure was initiallyproduced and its condition when positioned on the inner tubular element.

The struts are free to bend relative to each other with minimal appliedforce when in an unconstrained state, such as when the outer tubularelement 200 is enlarged or inflated, because of their relatively smallthicknesses and widths. When the structural member 300 is bent in itsunconstrained state based on an applied bending load, the strutsrearrange themselves to accommodate the changed mechanical condition, asschematically represented in FIG. 15. In FIG. 15, the longitudinal andserpentine struts have rearranged themselves to the lowest energyconfiguration available with the imposed curvature, preserving thelength and interconnection of the struts. In the concave portion of thesupport structure, the longitudinal struts are brought closer together,which approach is limited by the serpentine struts which are put intension, and the angle 336 becomes more acute. The acute angle betweenadjacent longitudinal and serpentine struts helps in the force transferbetween longitudinal struts as they rearrange themselves. On the convexside of the bend, the longitudinal struts tend to separate in someareas, subject to the restrictions of the attached serpentine struts andnearby longitudinal struts.

When the support structure is incorporated into catheters as describedherein, rearrangement of the struts occurs with relatively low forcerequired when the structural support element is unconstrained, or in atracking mode, such as when the outer tubular element is enlarged,expanded or separated from the structural support element. When thestructural support is constrained, such as when the catheter is in asupport mode, such as when the outer tubular element is collapsed orpressing against the structural support element, rearrangement of thestruts either does not occur or occurs at a much higher applied forcecompared to that in the unconstrained condition. The relatively highdegree of interconnectedness between the struts allows for flexibilityof the support structure to bend, but the points of interconnectionbetween struts limit the degrees of freedom in which the struts mayrearrange themselves. These factors can be changed by increasing ordecreasing the number of nodes per unit length, increasing or decreasingthe number of struts at a node, separate the struts into groups ofstruts and have one group of struts connected at more nodes and anothergroup of struts connected at fewer nodes, and similar variations.

In one exemplary catheter configuration, the length of the catheterdistally from the catheter hub is approximately 36 inches orapproximately 90 cm, and the length of the variable flexible portionwith the support structure 300 and the outer tubular element 200 isapproximately 8 inches or 20 cm. The portion of the catheter shaft thatcan include a variable flexible portion can be greater or lesser thanthis example.

The structural support element can take a number of configurations,especially considering the number of stent configurations that have beendeveloped. As one example of an alternative structural support element(FIG. 16), a support element 400 includes a cell 402 forming the basisof a repeating pattern, extending longitudinally and circumferentially.The cell 402 forms part of a helical pattern where the cell includes arectangular frame 404 having four sides and defining an opening 406.Each cell is separated from a longitudinally adjacent cell by a lasercut separation, forming the helically wound ribbon. The openings 406receive flexible portions of the outer tubular element when collapsed orpressing against the structural support element, thereby helping tolimit or restrict movement by mechanical engagement or frictionalresistance. In an alternative configuration, the cells 402 can take anon-helical configuration, for example with two or morecircumferentially adjacent cells connected together as shown in FIG. 16,or connected at one or more nodes (not shown) providing greaterflexibility between circumferentially adjacent cells. Longitudinallyadjacent cells can also be connected at one or more nodes (not shown) asa function of the desired flexibility in the constrained andunconstrained states.

In another example of a structural support element (FIG. 17), structuralsupport element 410 is formed from a helically cut tube or helicallywound ribbon. The structural support element includes a longitudinallyextending projection 412 in one part of the winding extending into acomplementary longitudinally extending cavity for 14 in an adjacentwinding. Windows or apertures (not shown) may be provided interior toedge surfaces of windings of the helix to provide frictional engagementsurfaces with the outer tubular element.

Adjustment of the flexibility or stiffness of a portion of the catheter100/100A/100B is used to allow the catheter to track a path in a vessel,for example over a guidewire or other guide device, and alternately toprovide structural support within the vessel when desired, for exampleto support passage of an intervention device or the like. In a trackingmode, the inner tubular member is flexible for easy track ability, andkink resistant to minimize damage during use and to provide suitableforce transmission along the long axis of the catheter for pushing andadvancing through the vessel. In the tracking mode when the structuralsupport element is flexible and not constrained, the struts of thestructural support element are free to bend, adjust and realign and movefreely, subject to the positioning of adjacent struts. The struts alignto the lowest energy configuration possible. When the catheter ispositioned as desired, the structural support element is pressed betweenthe outer tubular element and the inner tubular element, therebybecoming constrained and the struts are no longer free to move relativeto each other or relative to the adjacent surfaces without a significantamount of force. In the constrained or supportive configuration, thestructural support resists bending of the catheter, reducing itsflexibility and increasing its stiffness. The configuration is analogousto a clutch, whereby disengaging the outer tubular element from thestructural support element and further away from the inner tubularelement allows free motion of the structural support element and thestruts therein, as may be limited by the bending limitations in thestructural support element per se. Applying a vacuum or negativepressure or removing inflation fluid from inside the outer tubularelement engages the clutch structure, mechanically linking the outertubular element, the structural support element, and the inner tubularelement, rendering the catheter structure in the area of the structuralsupport element less flexible, and better able to support devices to bepassed through the catheter lumen.

In operation, a fully assembled catheter assembly 100/100A/100B isplaced in a tracking configuration by injecting fluid into the cavity206 within the outer tubular element 200, or otherwise increasing thepressure in the cavity. The tubular element is expanded or enlarged sothat the outer tubular element releases or mechanically disengages fromthe structural support element 300, thereby reducing or eliminating thefrictional resistance to bending with the structural support element300. The pressure is maintained within the cavity 206 or the outertubular element is otherwise maintained in the inflated or enlargedconfiguration. The catheter assembly is introduced into a body lumen,for example through a trocar, introducer, or other structure and movedthrough vasculature 500 (FIGS. 18-20), for example with the assistanceof a guidewire 502. As the guidewire 502 is moved to a new position, asillustrated in FIG. 18, the catheter 100/100A/100B is advanced over theguidewire in the catheter tracking mode. When the catheter has reachedthe desired location, such as illustrated in FIG. 19, the catheterassembly can be placed in the support mode by withdrawing fluid orapplying negative pressure to the lumen in fluid communication with thecavity 206, or by allowing the recoil or memory of the inflated outertubular element 200 to return toward its relaxed state, contracting intomechanical engagement or contact with the structural support element,and applying pressure to the structural support element and clamping thestructural support element between the outer and inner tubular elements.The flexible wall of the outer tubular element can also bulge into theopenings 303 between struts of the structural support element 300 (andpossibly contacting the outer surface 154 of the inner tubular element),thereby increasing the mechanical engagement or frictional forceresisting movement of the structural member relative to adjacentsurfaces, and thereby increasing the stiffness and support of thecatheter assembly. The reinforcement, for example the coil 158 in theinner tubular element, resists deformation of the inner tubular member,for example due to any compressive loading from the outer tubularmember, either alone or in combination with any bending load. In theexamples herein, the inner tubular element is substantiallyincompressible for the pressure loads that would be experienced undernormal operating conditions. The guidewire can then be withdrawn andreplaced by an interventional or other device 504 (FIG. 20) to carry outthe desired procedure, which may also have its own structural supportelement and flexible outer tubular element for adjustable support. Thecatheter assembly can then be withdrawn after returning the catheterassembly to a tracking mode, which may include reinserting a dilator,and then withdrawn in accordance with conventional methods.

Before the catheter is introduced into a lumen, and as the catheter istransiting a body lumen such as depicted in FIG. 18, the catheter can bein the tracking or flexible mode in the area of the structural supportmember. In that configuration, the catheter takes a number of shapesconfigurations, for example after manufacture the catheter can bestraight, including the variable stiffness region in the area of thestructural support member, and while the catheter is transiting the bodylumen, the catheter including the variable stiffness region will takeshape configurations conforming to the body lumen. In those shapeconfigurations, while the structural support member is released or freeto adjust its shape, the structural support member can have a number ofconfigurations. One configuration is illustrated in FIG. 15, in whichthe struts have rearranged themselves to the lowest-energy configurationimposed on it by the wall of the inner tubular member. However, whenpart or all of the structural support member takes on a fixed shapeconfiguration, for example by being sandwiched, pressed or squeezedbetween the inner and outer tubular elements, the structural supportmember and the surrounding catheter structure maintains the fixed shapeconfiguration, which is also the configuration of the surrounding lumenwall. As a result, the variable shape portion of the catheter adopts theshape of the surrounding lumen and does not substantially change thatshape until released. For example, once the catheter has been positionedas desired while in the tracking, flexible or released mode, such as inFIG. 19, the variable shaped portion of the catheter takes on a secondshape configuration different than previous shape configurations whilethe catheter was transiting the lumen. When the structural supportelement is sandwiched, laminated or fixed in the second shapeconfiguration, the variable shaped portion of the catheter applieslittle if any force 506 or pressure on the lumen wall as a result of thetransition from tracking or flexible mode to the support or fixed modein the second shape configuration. If the catheter were theoreticallyable to be lifted from the body lumen without having to transit thelumen passageway again, it would be seen that the catheter maintains theshape of the lumen it has adopted as though it has shape memory. Inother words, the variable shaped portion of the catheter in going fromthe tracking or flexible mode to the support or fixed mode applieslittle if any force on the adjacent lumen wall. Such results can beillustrated with a three-point bending flexural test with the variableshaped portion of the catheter arranged in a second shape configuration,and the force measured before and after fixing or pressing thestructural support member would not be very different. For example, theforce difference could be approximately 20%-25%, and could be in therange of 15-25%, and with the configuration of the structural supportmember 300 illustrated in FIGS. 10-13, can be less than 10% (force afterfixing or pressing the structural support member minus the force beforefixing or pressing the structural support member divided by the forcebefore).

A difference between the tracking mode and the support mode can beillustrated by comparing forces used to deflect a straight catheterassembly at the area of the variable stiffness. With a substantiallystraight catheter, a middle portion or other selected portion of thevariable stiffness area can be bent for an inch or other selecteddistance by having a normal force applied and measuring the forcerequired to move the selected distance. The force is measured when thecatheter is in the tracking mode or a more flexible state, and when thecatheter is in the support mode or a more rigid or stiff and lessflexible state. In one example where the outer tubular element iscompletely spaced apart from the underlying structural support memberand the catheter bent 1 inch, the measured force is about 0.38 poundsforce (lbf.). The catheter is then returned to a straight configuration,and placed in the support mode or with the outer tubular member pressingagainst the structural support member and bent 1 inch. The measuredforce is about 0.54 pounds force. A Bend Force Ratio of the Support ModeForce divided by the Tracking Mode Force in this example isapproximately 1.42. Ratios greater than one provide a desirable catheterconfiguration, and ratios of approximately 1.2 and above are moredesirable.

The catheter assembly can be assembled in a number of ways, including inpart conventional methods for assembling a catheter. In one method(FIGS. 21-28) a mandrel assembly 600 is used, similar to conventionalassembly apparatus. The mandrel assembly is selected to have a mandrel602 to provide the desired size catheter with the selected internaldiameter. In one process, the inner tubular member 150 is assembled bysliding a polytetrafluoroethylene liner over the mandrel 602 andapplying a braid or coil reinforcement over the liner. An extrusion isapplied over the braid or coil reinforcement, after which the layers aresecurely laminated inside a removable heat shrink tube to merge all ofthe components together into the inner tubular member 150. One or moreholes or apertures 164 are formed in the laminate, extending completelythrough, in the area where the structural support element will bepositioned. The structural support element is formed for example byfocused laser cutting a monolithic metal tube according to the desiredpattern. The structural support element 300 is placed over the tubularmember 150 and positioned as desired. It may be tack bonded at itsdistal and proximal ends to secure it to the inner tubular member forassembly.

The mandrel with the inner tubular member assembly is then inserted intoa tubular loading tool 604 (FIGS. 23-26) with the structural supportelement within a barrel 606 of the loading tool. The barrel 606 caninclude multiple parts, for example to be separated for inserting themandrel and inner tubular member. The loading tool includes an O-ringseal 608 at a distal portion for providing an airtight seal around theinner tubular member and mandrel. The loading tool 604 also includes apressurization port 610 proximal of the seal 608 for providingpressurized air or other pressurized fluid around the outside of theinner tubular element extending toward the distal end of the tubularelement. The barrel 606 includes an annular lip or ridge 612 at a distalend for receiving one end of an inflatable tubular element 614 to besealed around the barrel with an O-ring seal or other seal element 616.The parts of the barrel can be separated and the proximal portion placedover the proximal portion of the mandrel and inner tubular element, andthe distal portion placed over the structural support element and thetwo parts brought together and sealed. The inflatable tubular element614 is applied to the distal portion of the barrel and sealed with theseal 616. As illustrated in FIG. 23, the relaxed state of the inflatabletubular element 614 is less than the outer diameter of the structuralsupport element 300, and FIG. 23 shows the relationship schematicallyand greater spacing between the inflatable tubular element and themandrel 602 for ease of illustration. The opposite end of the inflatabletubular element is closed, for example with a closure knot, clip,ligation or the like. Inflation pressure is then applied at theinflation port 610 to inflate the inflatable member 614, as illustratedin FIG. 24, for example approximately 40 psi and possibly as much as80-100 PSI. The applied pressure inflates or expands the inflatablemember diametrically. When the inflatable member is stabilized, themandrel and inner tubular member assembly are slid inside the outertubular element 614 (FIG. 25) so that the inflatable member is suitablypositioned over the structural support member and an underlyingassembly. Pressure is then removed from the inflatable member, forexample through the pressurization port, and the inflatable membercollapses around the structural support member and the adjacent portionof the inner tubular member (FIG. 26). The assembly is then removed fromthe loading tool 604 (FIG. 27) and the inflatable member trimmed to thedesired length around the structural support member. The outer tubularelement 200 is then bonded at 618 and 622 the inner tubular element, andfurther trimmed if necessary (FIG. 28). The mandrel 602 is then replacedby a smaller mandrel 622, and the tip of the catheter is re-flowed toreduce its diameter to that of the smaller mandrel, to provide thedesired interference fit with an appropriate dilator tip. The mandrel622 is then removed, and the tubular assembly bonded or otherwisesecured at its proximal end to a proximal hub, for example catheter hub104 (FIGS. 1-2).

With selection of suitable material for the outer tubular element 200,resilience or pressure memory can be incorporated into the outer tubularmember on assembly, for example by using a relaxed tubular member havingan inside diameter in the relaxed condition less than the structuralsupport member and possibly even less than the inner tubular element.Inflation of the inflatable material allows easy assembly of the outertubular element onto the catheter assembly to provide the desiredresilience so that the outer tubular member can apply an appropriatepressure to the structural support element.

Other structures and assemblies can be used in addition to or asalternatives to those described herein for controllably changing thesupport provided in a lumenal assembly, for example a catheter assemblysuch as those described herein. In the examples shown in FIGS. 29-44,structures with the same reference numbers have the same or similarstructures and functions as described herein. In one exemplaryalternative, described in conjunction with FIGS. 29-32, an assembly forcontrollably varying a stiffness of a catheter assembly 100A includes amedial member that is an assembly having a structural support assembly300A. The structural support assembly 300A includes an inner structuralsupport member 350 extending about an adjacent portion of the catheterwall 154 in a manner similar to the structural support 300 describedherein. The inner structural support member 350 can be configured tohave the structure and function of any of the structural support membersdescribed herein, and in the present configuration extendscircumferentially completely around the adjacent portion of the catheterlumen.

In the illustrated configuration in FIGS. 29-32, the structural supportassembly 300A includes an outer structural support member 352 laterallyoutward of the inner structural support member 350. In the presentexample, the outer structural support member 352 extendscircumferentially around the adjacent portion of the catheter lumen,outboard of the inner structural support member, and interior to theadjacent surface 208 of the inflation lumen 200. The outer structuralsupport member 352 can have a structure and function identical to thatof the inner structural support member 350, or it can have a structureand/or function different than that of the inner structural member. Theouter structural support member 352 can be configured to have thestructure and function of any of the structural support membersdescribed herein.

The structural support assembly 300A may also include, but need notinclude, a secondary material such as a sleeve 354. The sleeve in theexemplary configuration extends and is positioned between the inner andouter structural support members, coaxial therewith, but may be insideor outside both structural support members. In the present example, thesleeve material is a flexible material, and may include surfacecharacteristics allowing free sliding movement of the adjacentstructural support members, or providing frictional engagement to reducefree sliding movement of the adjacent structural support membersrelative to the sleeve material. The sleeve may be a continuous tubularelement, may be formed with a porous configuration, may be a random ornon-random mesh material, or may have other configurations as desired.

The configurations illustrated in FIGS. 29-30 show the inflation lumenin an expanded or inflated configuration, providing a reduced measure ofstructural support to the assembly. When inflation fluid is removed orallowed to escape or evacuate the interior of the inflation lumen 200,spacing between the inner and outer structural support elements and thesleeve and the adjacent surfaces of the inflation lumen and the catheterlumen decreases. With sufficient removal or outflow of inflation fluid,the inflation lumen 200 may contact the adjacent surfaces of the outerstructural support member 352. Additionally, interior surfaces of theouter structural support member 352 may contact the outer surface of thesleeve 354, and the inner surface of the sleeve 354 may contact theadjacent outer surfaces of the inner structural support member 350.Interior surfaces of the inner structural support member may contact theadjacent surface 154 of the catheter lumen, and the assembly may provideadditional stiffening, rigidity or structural support for the catheterassembly when in the configuration illustrated in FIGS. 31-32.

In another configuration of a catheter assembly having controllablyvariable stiffness or rigidity in at least a portion of the catheterassembly, a portion of a catheter lumen 102A (FIGS. 33-36) may beenclosed in or surrounded by an inflation lumen or inflation balloon700. The inflation lumen 700 may enclose only the adjacent portion ofthe catheter lumen, or may enclose the portion of the catheter lumenalong with other structures and/or materials, including possiblestructures and/or materials between the inflation lumen 700 and thecatheter lumen 102A. In the present illustrated example, the inflationlumen 700 surrounds the catheter lumen 102A without any intermediatestructural material between the inflation lumen 700 and the catheterlumen 102A. in the present example, the inflation lumen 700 is formedfrom a relatively non-compliant material. When the inflation lumen 700deflates or contracts inwardly around the catheter lumen 102A, forexample to contact the catheter lumen, and for example with removal ofinflation fluid or otherwise similar to methods described herein, one ormore portions of the inflation lumen 700 form one or more pleats 702(FIGS. 35-36). One or more pleats on the inflation lumen 700 providesstructural support to the assembly. In the illustrated example, a pleatforms on the interior of a curved surface of the assembly, or on aconcave surface of the assembly. In the configuration illustrated inFIGS. 35-36, the inflation lumen 700 has a deflated configuration wherethe lumen makes substantial contact with adjacent surfaces of thecatheter lumen.

In another exemplary alternative illustrated in FIGS. 37-40, theassembly is identical to or substantially identical to that describedwith respect to FIGS. 29-32 but the medial member is omitting one or theother of the outer or inner structural support 352 (as illustrated) or350, respectively. In an alternative configuration not illustrated, thestructural support assembly can omit the inner structural support 350and instead include the sleeve 354 and the outer structural support 352.Other configurations of a medial member of an assembly having astructural support member and a secondary material can be used.

In a further exemplary alternative illustrated in FIGS. 41-44, anassembly 100A includes an inflation lumen or balloon 200A incorporatingwith it a structural support material 300C. As illustrated, thestructural support material 300C is embedded in or formed in part of theinterior of the material of the inflation lumen 200A. In otherconfigurations, the structural support material 300C may be formed oneither or both of the interior or exterior surfaces of the inflationlumen 200A. In this example, the structural support material 300C may beany of the structural support elements described herein.

In any of the assemblies of the type described herein, and for any ofthe support members/structural supports or support structures describedherein, the support structure can be made more or less amenable to easymovement within the assembly for example when an outer tubular elementis in a relaxed state or otherwise pressing the support structureagainst the outer surface of the inner tubular structure 150, orotherwise when the support structure is contacting an outer surface ofthe inner tubular structure. To provide for easier movement, forexample, steps can be taken to render the adjacent surfaces of thesupport structure smoother than otherwise, and/or change the structuralconfiguration of the support structure, for example by decreasing thedensity of the limbs and/or their interconnection. In one example,easier movement can be accomplished by electro-polishing of a nytinolsupport structure.

In addition to other ways described herein, configurations of a supportstructure can also be used to contribute to higher frictional forceswhen in contact with one or more adjacent surfaces, includingconfigurations described previously. In one example, a support structuremay be configured so that one or more surfaces on the support structurefacing respective adjacent structures on another part of the lumenalassembly have surface geometries that are other than smooth, or that arediscontinuous, nonuniform or otherwise changed to be other than smooth.For example, the support structure has surfaces facing one or more ofthe adjacent structures, for example facing the tubular member 150 outersurface or facing the tubular element 200 inner surface, and such facingsurfaces will have surface geometries. The relevant surface geometriesof the structural support illustrated in FIGS. 12-13, for example, aresubstantially smooth. Alternatively, one or more of the surfacegeometries can be other than smooth, have discontinuities ornon-uniformities. For example, a support structure may have an elementsuch as a limb, or a plurality of limbs, that may be configured with afacing surface geometry that is non-smooth, for example to include oneor more raised structures extending outwardly from one or more facingsurfaces a desired distance so that the raised structure can contact arespective surface adjacent the facing surface for generating higherfrictional force when they contact. In examples of the presentassemblies, the adjacent surfaces can be adjacent surfaces on either orboth of the outer tubular element or the inner tubular structure, or onintermediate or associated structures such as those described withrespect to FIGS. 29-44.

An example of a support structure configuration that can contribute tohigher frictional forces in the assembly for resisting movement orgeometry changes with raised structures is a support structure 360(FIGS. 45-47). In the present example, the support structure 360 isdescribed as having raised structures on an interior facing surface toface an adjacent outside surface on the inner tubular structure 150, butit should be understood that raised structures can instead oradditionally be placed on a facing surface facing an adjacent insidesurface of the outer tubular element in the configuration shown in FIGS.45-47. The present description has the raised structures for the supportstructure 360 on the inside surface of the support structure, butidentical raised structures or different raised structures can be on theoutside surface of the support structure.

The support structure 360 is similar to the support structure 300 inthat it includes cells of limbs in the form of primary longitudinalstruts 362 and secondary longitudinal struts 364 interconnected byserpentine struts 366, and the cells generally repeat. Otherconfigurations are possible, and non-smooth surface geometries can beincorporated in any of the support structures as described herein orsimilar thereto. In the present configuration of the support structure360, the primary longitudinal strut is less than twice the length of thesecondary longitudinal strut but greater than 1½ times the length, ascan be seen by the relative number of, substantially equally spaced inthe illustrated example, raised structures on each of the longitudinalstruts. Each primary longitudinal strut at each end is coupled torespective pairs of oppositely arranged serpentine struts 366. Eachserpentine strut in the present example includes an enlarged portion 368for providing a support for a raised structure. However, it isunderstood that fewer than all or that any number of struts can includeraised structures, in any desired distribution, density, geometry andconfiguration, as desired, while the illustration shows all struts withraised structures, equally spaced, uniformly distributed, and withidentical geometries.

In the example of the support structure 360 illustrated in FIGS. 45-47,each strut includes a raised structure 370. In the present example, eachof the raised structures 370 are identical to the others, and arerelatively evenly distributed across the longitudinal struts and acrossthe enlarged portions 368 of the serpentine struts 266. In alternativeconfigurations, the raised structures can be different from each other,and can be distributed unevenly or randomly, omitted from one or morelimbs, or otherwise. One or more of the raised structures can be createdaccording to a defined process at defined locations, according to adefined process at random locations, or according to a random process atrandom locations. In the present example, each of the raised structures370 are identical to the extent that manufacturing or formationprocesses allow any predictable precision in the formation of the raisedstructures 370 or the support structure 360 having such raisedstructures. However, it is understood that conventional manufacturingprocesses may produce raised structures with variations in location on astrut, geometry and orientation, and the visual appearance of thegeometry may be different from a drawing characterizing the structure orfrom which the structure was created by currently available formingtechniques.

The raised structures can take a number of configurations. In thepresent example, they are illustrated as being substantially roundhaving a relatively constant and consistent heights relative to eachother and relative to the underlying strut. However, it should beunderstood that the actual resulting raised structures may not beidentical in height or in cross-sectional configuration as between oneanother, or from one manufacturing lot to another. The raised structuresare illustrated in the present example as being consistent incross-section and also in height for simplicity. The geometries of theactual raised structures may vary. In one example of a configuration forthe raised structures, the raised structure can have a height 372 lessthan a height or thickness 374 of the strut. If the raised structure 370were configured to be round, the raised structure could have a diameteror equivalent dimension 376, which may be less than a width 378 of thestrut from which the raised structure 370 extends. As illustrated, theratio of the height of the raised structure is less than 50%, and theratio of the diameter is also less than 50% of the width of the strut.These ratios may vary from about 10% to about 50%, respectively, withresulting variations in the frictional forces developed in the assemblyfor resisting movement or geometry changes in the assembly.

For a given assembly of a support structure and adjacent surfaces, theraised structures can decrease the surface area of contact between thestruts and the adjacent surfaces, such as between the struts and theouter surface of the inner tubular element, relative to such an assemblywithout the raised structures. Decreasing the surface area of contact,such as by adding the raised structures, increases the force per unitarea for a given configuration of the assembly in the area of thesupport structure, which produces an increase in the traction orfrictional engagement between the support structure and the adjacentouter surface of the inner tubular element. For example, relative tocomparable structures with the support structure 300 as illustrated inFIGS. 4 and 6, a support structure 360 having raised structures 370 willapply a higher force per unit area for each raised structure for a givenouter tubular element 200. The higher force per unit area can occur whenthe outer tubular element is in its relaxed state or when the outertubular element is contracted, such as when fluid is removed or pressurewithin the outer tubular element is reduced, for example so that theouter tubular element applies pressure to the structural support 360squeezing it between the outer and inner tubular elements, and therebychanging the mechanical properties, stiffness and flexibility of thatportion of the assembly. In the present example, the raised structuresengage an outer surface on the inner tubular element 150. During theengagement, for example as illustrated in FIG. 47, the pressure appliedto the struts 366 forces the raised structures 370 into the plasticsurface of the inner tubular element 150. The raised structures engagethe material creating frictional engagement, thereby changing themechanical properties, stiffness or flexibility of that portion of theassembly. For a given pressure applied by the outer tubular element 200,the raised structures 370 produce a higher force per unit area againstthe outer surface of the inner tubular element 150.

Raised structures can be created on surfaces of the support structureaccording to a pattern, or randomly. They can be created as raisedstructures per se, or they can be produced by removing adjacentmaterial, or they can be generated as a combination of raised anddepressed areas or cavities. Raised structures can be formed in a numberof ways. In one process, raised structures can be photochemically milledduring the formation of a stent or stent-like structure, such as any ofthe support structures of the type described herein, and the supportstructure formed accordingly. For example, raised structures can beformed on a planar stent pattern and then rolled to form the finalsupport structure, with the raised structures on the interior surface,exterior surface, or possibly both depending on the desired method offormation. In another process of forming raised structures on a supportstructure, the support structure can be created as desired, and thencovered with a photomask or photoresist, which can then be used tocreate a random or non-keyed pattern of raised structures.

In another example of lumenal or tubular structures, including any ofthose described herein, a surface of an inner tubular structure facingan adjacent surface of a support structure such as any of thosedescribed herein can be formed other than entirely smooth, for examplewith surface roughness different than the surface configuration of otherparts of the inner tubular structure, surface dimples, surface cavitiesor other surface discontinuities. The facing surface of the innertubular structure can be other than entirely smooth to increase thefrictional engagement between the surface and the adjacent supportstructure.

In any of the lumenal members described herein, including for examplethe catheter assembly 100, and 100A, the lumenal members may include oneor more medical devices associated with the assembly, for exampleadjacent the distal portion of the assembly. In one example (FIG. 48), acatheter assembly 100B is identical to the catheter assembly 100A, andhas the same structures and functions as described with respect tocatheter 100A, for example as described in conjunction with FIGS. 8-9,with the addition of one or more medical devices. In the illustratedexample, medical device 750 is positioned on an external surface of thecatheter shaft 102A, for example as illustrated over and contacting theseam or seal between the catheter shaft and the inflation lumen.Alternatively, the medical device 750 can be mounted on or supported bya portion of the catheter shaft (not shown) extending distally of theseam or seal. The medical device can be configured to extend around thecatheter shaft, or may be configured to extend over an arcuate portionof the shaft. The medical device can extend longitudinally and radiallyas desired for the intended purpose of the device.

In a further configuration of the assembly 100B is illustrated in FIG.48, the medical device 750 alternatively or additionally can besupported adjacent a distal portion of the catheter shaft 102A, asillustrated at 750′. The characteristics and configuration of themedical device 750′ can be the same as or different from the medicaldevice located distally of the inflation lumen.

The medical device 750/750′ can be any number of devices. The medicaldevice can be any one or more of a diagnostic or therapy device,including but not limited a device for angioplasty, ablation,angiography, occlusion, radiation, visualization, or a stent.

Having thus described several exemplary implementations, it will beapparent that various alterations and modifications can be made withoutdeparting from the concepts discussed herein. Such alterations andmodifications, though not expressly described above, are nonethelessintended and implied to be within the spirit and scope of theinventions. Accordingly, the foregoing description is intended to beillustrative only.

1. A flexible lumenal assembly configured for transiting a body lumen comprising a flexible lumenal member extending longitudinally and a medial member having a structural support member having a plurality of limbs, at least one limb of which extends other than longitudinally and that has a facing surface facing at least one surface on either of the flexible lumenal member or an outer element, wherein the facing surface has a non-smooth surface geometry including at least one raised portion raised from the facing surface, and wherein the medial member extends outside a portion of the flexible lumenal member and inside an outer member extending over the medial member wherein the outer member is configured to selectively apply pressure to the medial member.
 2. The assembly of claim 1 wherein the outer member is configured to releasably compress the structural support member.
 3. The assembly of claim 1 wherein the structural support member is a tubular structural support member.
 4. The assembly of claim 1 wherein the structural support member is a tubular mesh.
 5. The assembly of claim 4 wherein the tubular mesh includes a non-random tubular mesh.
 6. The assembly of claim 1 wherein the structural support member is positioned in a cavity between the flexible lumenal member and the outer member
 7. The assembly of claim 1 wherein the outer member substantially encloses the structural support member.
 8. The assembly of claim 1 further including a passageway for fluid to enter and exit an area between the structural support member and the outer member.
 9. The assembly of claim 1 wherein the outer member is flexible.
 10. The assembly of claim 1 wherein the outer member is resiliently flexible.
 11. The assembly of claim 1 wherein the outer member is a balloon.
 12. The assembly of claim 1 wherein the outer member is configured to have an enlarged configuration and a reduced configuration, and wherein in the reduced configuration the outer member applies pressure to the structural support member.
 13. The assembly of claim 12 wherein the structural support member is sandwiched, concentric, layered, or positioned between the lumenal member and the outer member.
 14. The assembly of claim 12 wherein the assembly is configured such that application of pressure by the outer member to the structural support member presses the structural support member against the lumenal member.
 15. The assembly of claim 12 wherein the assembly is configured such that enlargement of the outer member relieves at least part of the pressure on the structural support member.
 16. The assembly of claim 15 wherein the assembly is configured such that enlargement of the outer member relieves all of the pressure on the structural support member.
 17. The assembly of claim 15 wherein the assembly is configured such that relieving pressure on the structural support member includes reducing a surface area of contact between the outer member and the structural support member.
 18. The assembly of claim 1 wherein the structural support element includes a plurality of component elements and wherein a transverse cross-section of the structural support element includes at least two component elements.
 19. The assembly of claim 18 wherein a transverse cross-section of the structural support element includes at least three component elements.
 20. The assembly of claim 18 wherein at least two of the component elements have different sizes.
 21. The assembly of claim 20 wherein at least two of the component elements have different transverse cross-sectional areas.
 22. The assembly of claim 20 wherein at least two of the component elements have different lengths.
 23. The assembly of claim 18 wherein the structural support element includes at least first and second groups of component elements wherein each of the component elements in the first group is different from each of the component elements in the second group.
 24. The assembly of claim 23 wherein there are more component elements in the second group than in the first group.
 25. The assembly of claim 23 wherein there are twice as many component elements in the second group than in the first group.
 26. The assembly of claim 23 wherein respective ones of the component elements in the first group are coupled to respective ones of the component elements in the second group.
 27. The assembly of claim 18 wherein the at least two component elements are connected to each other.
 28. The assembly of claim 18 wherein the at least two component elements are connected to each other at respective ends.
 29. The assembly of claim 18 wherein the at least two component elements include at least one smooth surface.
 30. The assembly of claim 18 wherein the structural support element extends longitudinally a first distance, and wherein one of the component elements includes a component element less than the first distance.
 31. The assembly of claim 30 wherein each of the component elements in the structural support element includes respective lengths less than the first distance.
 32. The assembly of claim 18 wherein the structural support element includes at least three component elements having a first transverse cross-sectional area, and at least three components having a second transverse cross-sectional area less than the first transverse cross-sectional area.
 33. The assembly of claim 18 wherein the component elements are distributed around a perimeter of the structural support element substantially uniformly.
 34. The assembly of claim 18 wherein each of the component elements is coupled to at least one other component element.
 35. The assembly of claim 34 wherein each of the component elements is coupled at each end respectively to at least one other component element.
 36. The assembly of claim 18 wherein each of the component elements extends substantially linearly.
 37. The assembly of claim 18 wherein the at least two component elements includes first and second component elements and wherein the first and second component elements are coupled to each other at an angle.
 38. The assembly of claim 37 wherein the angle is greater than zero and less than 90°.
 39. The assembly of claim 1 wherein the flexible lumenal member includes reinforcement.
 40. The assembly of claim 39 wherein the reinforcement includes either a coil or a braid embedded in the flexible lumenal member.
 41. The assembly of claim 1 wherein the flexible lumenal member is substantially incompressible under normal operating conditions.
 42. The assembly of claim 1 wherein the structural support member is a stent.
 43. The assembly of claim 1 wherein the assembly forms a portion of a catheter.
 44. The assembly of claim 1 further including a catheter hub having an injection port.
 45. The assembly of claim 1 further including a fluid lumen coupled to a space between the outer element and the structural support member, and extending off-center from a central axis of the assembly.
 46. The assembly of claim 45 wherein the fluid lumen extends along an outside wall of the flexible lumenal member.
 47. The assembly of claim 1 configured to receive a guidewire.
 48. The assembly of claim 1 configured to receive a dilator element or therapy device.
 49. The assembly of claim 1 configured to receive a syringe.
 50. A flexible lumenal assembly configured for transiting a body lumen comprising a lumenal element extending longitudinally, a tubular mesh having a plurality of limbs extending longitudinally and circumferentially around a portion of the lumenal element and a tubular member at least partly sealed to the lumenal element and wherein all portions of the tubular mesh are positioned between a respective surface of the lumenal element and a respective surface of the tubular member and the tubular mesh includes at least one facing surface facing one of the luminal element and the tubular member and at least one limb has a varying thickness.
 51. The assembly of claim 50 wherein the lumenal element includes reinforcement.
 52. The assembly of claim 50 wherein the lumenal element is substantially incompressible in normal operating conditions.
 53. The assembly of claim 50 wherein the tubular member is resiliently flexible.
 54. The assembly of claim 50 wherein the tubular member is configured to be biased for pressing against the tubular mesh.
 55. The assembly of claim 50 wherein the tubular member is sufficiently flexible to have surface portions extend between individual components of the tubular mesh.
 56. The assembly of claim 50 wherein the tubular mesh is configured in the assembly to have an inside diameter substantially the same as an outside diameter of the adjacent lumenal element.
 57. The assembly claim 50 wherein the tubular mesh includes a plurality of component elements and wherein a plurality of the component elements include longitudinally extending component elements when the lumenal element extends substantially straight.
 58. The assembly of claim 57 wherein a first plurality of longitudinally extending component elements extends circumferentially around the tubular mesh and another plurality of longitudinally extending elements extends circumferentially around the tubular mesh and shifted longitudinally from the first plurality of longitudinally extending elements.
 59. The assembly of claim 58 wherein the first plurality of longitudinally extending elements comprises at least three longitudinally extending elements.
 60. The assembly of claim 58 wherein the first plurality of longitudinally extending elements includes six longitudinally extending elements.
 61. The assembly of claim 57 further including a plurality of angularly extending elements extending other than parallel to the longitudinally extending elements when the lumenal element extends substantially straight.
 62. The assembly of claim 61 wherein each of the angularly extending elements include respective first and second ends and wherein each first and second end is connected to a respective longitudinally extending element.
 63. The assembly of claim 61 wherein the longitudinally extending elements have a size different from a size of the angularly extending elements.
 64. The assembly of claim 63 wherein the longitudinally extending elements have at least one of a larger transverse cross-sectional area or longer length.
 65. The assembly of claim 61 wherein the angularly extending elements extend at an angle to respective ones of longitudinally extending elements greater than zero and less than 90°.
 66. The assembly of claim 65 wherein the angle is between 5° and 30°.
 67. The assembly of claim 50 wherein the tubular mesh is a stent.
 68. The assembly of claim 50 wherein the lumenal element is a cylindrical tubular element.
 69. The assembly of claim 50 wherein the lumenal member is configured for receiving a guidewire or a therapy device.
 70. The assembly of claim 50 further including a lumen for receiving a fluid configured to allow the fluid to enter a space occupied by the tubular mesh between the tubular element and the lumenal element.
 71. A catheter assembly configured for transiting a body lumen comprising a lumenal element extending longitudinally, a structural support extending longitudinally and about a portion of the lumenal element and including surface variations on a facing surface of the structural support facing the luminal element wherein the surface variations are one of discontinuities, non-uniformities, raised structures or cavities, and a tubular element sealed at least in part to the lumenal element and extending on a side of the structural support outside of the lumenal element and configured such that the tubular element contacts at least a portion of the structural support to provide a first stiffness for the lumenal element adjacent the structural support and such that the lumenal element has a second stiffness lower than the first stiffness when contact between the tubular element and the at least a portion of the structural support is decreased. 72-79. (canceled)
 80. The apparatus of claim 71 wherein the facing surface with non-smooth surface or surface variations are formed as raised structures.
 81. The apparatus of claim 80 wherein the raised structures are distributed substantially uniformly.
 82. The apparatus of claim 80 wherein the raised structures have similar geometries.
 83. The apparatus of claim 80 wherein the raised structures have heights extending from the respective facing surface that are similar to each other.
 84. The apparatus of claim 80 wherein a plurality of the raised structures have a non-circular geometry in plan view.
 85. The apparatus of claim 80 wherein at least one of the raised structures has a height that is less than a thickness of the material from which the at least one raised structure extends.
 86. The apparatus of claim 80 wherein at least one of the raised structures is substantially centered widthwise relative to the material from which the at least one raised structure extends. 87-115. (canceled) 